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8024761: JSR 292 improve performance of generic invocation

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Use a per-MH one element cache for MH.asType to speed up MH.invoke; also cache enough MH constants to cache LMF.metafactory

Reviewed-by: twisti
This commit is contained in:
John R Rose 2013-10-05 05:30:38 -07:00
parent 1d4c1c6ee5
commit 62ee211c8d
11 changed files with 395 additions and 350 deletions

5
jdk/src/share/classes/java/lang/invoke/BoundMethodHandle.java

@ -360,6 +360,10 @@ import jdk.internal.org.objectweb.asm.Type;
return new Name(mh, mhName);
}
NamedFunction getterFunction(int i) {
return new NamedFunction(getters[i]);
}
static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);
private SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {
@ -394,6 +398,7 @@ import jdk.internal.org.objectweb.asm.Type;
private boolean isPlaceholder() { return clazz == null; }
private static final HashMap<String, SpeciesData> CACHE = new HashMap<>();
static { CACHE.put("", EMPTY); } // make bootstrap predictable
private static final boolean INIT_DONE; // set after <clinit> finishes...
SpeciesData extendWithType(char type) {

48
jdk/src/share/classes/java/lang/invoke/CallSite.java

@ -261,7 +261,7 @@ public class CallSite {
Object info,
// Caller information:
Class<?> callerClass) {
Object caller = IMPL_LOOKUP.in(callerClass);
MethodHandles.Lookup caller = IMPL_LOOKUP.in(callerClass);
CallSite site;
try {
Object binding;
@ -273,14 +273,44 @@ public class CallSite {
} else {
Object[] argv = (Object[]) info;
maybeReBoxElements(argv);
if (3 + argv.length > 255)
throw new BootstrapMethodError("too many bootstrap method arguments");
MethodType bsmType = bootstrapMethod.type();
if (bsmType.parameterCount() == 4 && bsmType.parameterType(3) == Object[].class)
binding = bootstrapMethod.invoke(caller, name, type, argv);
else
binding = MethodHandles.spreadInvoker(bsmType, 3)
.invoke(bootstrapMethod, caller, name, type, argv);
switch (argv.length) {
case 0:
binding = bootstrapMethod.invoke(caller, name, type);
break;
case 1:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0]);
break;
case 2:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0], argv[1]);
break;
case 3:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0], argv[1], argv[2]);
break;
case 4:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0], argv[1], argv[2], argv[3]);
break;
case 5:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0], argv[1], argv[2], argv[3], argv[4]);
break;
case 6:
binding = bootstrapMethod.invoke(caller, name, type,
argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
break;
default:
final int NON_SPREAD_ARG_COUNT = 3; // (caller, name, type)
if (NON_SPREAD_ARG_COUNT + argv.length > MethodType.MAX_MH_ARITY)
throw new BootstrapMethodError("too many bootstrap method arguments");
MethodType bsmType = bootstrapMethod.type();
MethodType invocationType = MethodType.genericMethodType(NON_SPREAD_ARG_COUNT + argv.length);
MethodHandle typedBSM = bootstrapMethod.asType(invocationType);
MethodHandle spreader = invocationType.invokers().spreadInvoker(NON_SPREAD_ARG_COUNT);
binding = spreader.invokeExact(typedBSM, (Object)caller, (Object)name, (Object)type, argv);
}
}
//System.out.println("BSM for "+name+type+" => "+binding);
if (binding instanceof CallSite) {

148
jdk/src/share/classes/java/lang/invoke/InvokeGeneric.java

@ -1,148 +0,0 @@
/*
* Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang.invoke;
import sun.invoke.util.*;
import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
/**
* Adapters which manage inexact MethodHandle.invoke calls.
* The JVM calls one of these when the exact type match fails.
* @author jrose
*/
class InvokeGeneric {
// erased type for the call, which originates from an inexact invoke site
private final MethodType erasedCallerType;
// an invoker of type (MT, MH; A...) -> R
private final MethodHandle initialInvoker;
/** Compute and cache information for this adapter, so that it can
* call out to targets of the erasure-family of the given erased type.
*/
/*non-public*/ InvokeGeneric(MethodType erasedCallerType) throws ReflectiveOperationException {
assert(erasedCallerType.equals(erasedCallerType.erase()));
this.erasedCallerType = erasedCallerType;
this.initialInvoker = makeInitialInvoker();
assert initialInvoker.type().equals(erasedCallerType
.insertParameterTypes(0, MethodType.class, MethodHandle.class))
: initialInvoker.type();
}
private static MethodHandles.Lookup lookup() {
return IMPL_LOOKUP;
}
/** Return the adapter information for this type's erasure. */
/*non-public*/ static MethodHandle generalInvokerOf(MethodType erasedCallerType) throws ReflectiveOperationException {
InvokeGeneric gen = new InvokeGeneric(erasedCallerType);
return gen.initialInvoker;
}
private MethodHandle makeInitialInvoker() throws ReflectiveOperationException {
// postDispatch = #(MH'; MT, MH; A...){MH'(MT, MH; A)}
MethodHandle postDispatch = makePostDispatchInvoker();
MethodHandle invoker;
if (returnConversionPossible()) {
invoker = MethodHandles.foldArguments(postDispatch,
dispatcher("dispatchWithConversion"));
} else {
invoker = MethodHandles.foldArguments(postDispatch, dispatcher("dispatch"));
}
return invoker;
}
private static final Class<?>[] EXTRA_ARGS = { MethodType.class, MethodHandle.class };
private MethodHandle makePostDispatchInvoker() {
// Take (MH'; MT, MH; A...) and run MH'(MT, MH; A...).
MethodType invokerType = erasedCallerType.insertParameterTypes(0, EXTRA_ARGS);
return invokerType.invokers().exactInvoker();
}
private MethodHandle dropDispatchArguments(MethodHandle targetInvoker) {
assert(targetInvoker.type().parameterType(0) == MethodHandle.class);
return MethodHandles.dropArguments(targetInvoker, 1, EXTRA_ARGS);
}
private MethodHandle dispatcher(String dispatchName) throws ReflectiveOperationException {
return lookup().bind(this, dispatchName,
MethodType.methodType(MethodHandle.class,
MethodType.class, MethodHandle.class));
}
static final boolean USE_AS_TYPE_PATH = true;
/** Return a method handle to invoke on the callerType, target, and remaining arguments.
* The method handle must finish the call.
* This is the first look at the caller type and target.
*/
private MethodHandle dispatch(MethodType callerType, MethodHandle target) {
MethodType targetType = target.type();
if (USE_AS_TYPE_PATH || target.isVarargsCollector()) {
MethodHandle newTarget = target.asType(callerType);
targetType = callerType;
Invokers invokers = targetType.invokers();
MethodHandle invoker = invokers.erasedInvokerWithDrops;
if (invoker == null) {
invokers.erasedInvokerWithDrops = invoker =
dropDispatchArguments(invokers.erasedInvoker());
}
return invoker.bindTo(newTarget);
}
throw new RuntimeException("NYI");
}
private MethodHandle dispatchWithConversion(MethodType callerType, MethodHandle target) {
MethodHandle finisher = dispatch(callerType, target);
if (returnConversionNeeded(callerType, target))
finisher = addReturnConversion(finisher, callerType.returnType()); //FIXME: slow
return finisher;
}
private boolean returnConversionPossible() {
Class<?> needType = erasedCallerType.returnType();
return !needType.isPrimitive();
}
private boolean returnConversionNeeded(MethodType callerType, MethodHandle target) {
Class<?> needType = callerType.returnType();
if (needType == erasedCallerType.returnType())
return false; // no conversions possible, since must be primitive or Object
Class<?> haveType = target.type().returnType();
if (VerifyType.isNullConversion(haveType, needType) && !needType.isInterface())
return false;
return true;
}
private MethodHandle addReturnConversion(MethodHandle finisher, Class<?> type) {
// FIXME: This is slow because it creates a closure node on every call that requires a return cast.
MethodType finisherType = finisher.type();
MethodHandle caster = ValueConversions.identity(type);
caster = caster.asType(caster.type().changeParameterType(0, finisherType.returnType()));
finisher = MethodHandles.filterReturnValue(finisher, caster);
return finisher.asType(finisherType);
}
public String toString() {
return "InvokeGeneric"+erasedCallerType;
}
}

239
jdk/src/share/classes/java/lang/invoke/Invokers.java

@ -44,6 +44,7 @@ class Invokers {
// exact invoker for the outgoing call
private /*lazy*/ MethodHandle exactInvoker;
private /*lazy*/ MethodHandle basicInvoker; // invokeBasic (unchecked exact)
// erased (partially untyped but with primitives) invoker for the outgoing call
// FIXME: get rid of
@ -74,21 +75,7 @@ class Invokers {
/*non-public*/ MethodHandle exactInvoker() {
MethodHandle invoker = exactInvoker;
if (invoker != null) return invoker;
MethodType mtype = targetType;
MethodType invokerType = mtype.invokerType();
LambdaForm lform;
final int MTYPE_ARG_APPENDED = 1; // argument count for appended mtype value
if (mtype.parameterSlotCount() <= MethodType.MAX_MH_INVOKER_ARITY - MTYPE_ARG_APPENDED) {
lform = invokeForm(mtype, false, MethodTypeForm.LF_EX_INVOKER);
invoker = BoundMethodHandle.bindSingle(invokerType, lform, mtype);
} else {
// At maximum arity, we cannot afford an extra mtype argument,
// so build a fully customized (non-cached) invoker form.
lform = invokeForm(mtype, true, MethodTypeForm.LF_EX_INVOKER);
invoker = SimpleMethodHandle.make(invokerType, lform);
}
invoker = invoker.withInternalMemberName(MemberName.makeMethodHandleInvoke("invokeExact", mtype));
assert(checkInvoker(invoker));
invoker = makeExactOrGeneralInvoker(true);
exactInvoker = invoker;
return invoker;
}
@ -96,43 +83,56 @@ class Invokers {
/*non-public*/ MethodHandle generalInvoker() {
MethodHandle invoker = generalInvoker;
if (invoker != null) return invoker;
MethodType mtype = targetType;
MethodType invokerType = mtype.invokerType();
LambdaForm lform;
final int MTYPE_ARG_APPENDED = 1; // argument count for appended mtype value
assert(GENERIC_INVOKER_SLOP >= MTYPE_ARG_APPENDED);
if (mtype.parameterSlotCount() <= MethodType.MAX_MH_INVOKER_ARITY - GENERIC_INVOKER_SLOP) {
prepareForGenericCall(mtype);
lform = invokeForm(mtype, false, MethodTypeForm.LF_GEN_INVOKER);
invoker = BoundMethodHandle.bindSingle(invokerType, lform, mtype);
} else {
// At maximum arity, we cannot afford an extra mtype argument,
// so build a fully customized (non-cached) invoker form.
lform = invokeForm(mtype, true, MethodTypeForm.LF_GEN_INVOKER);
invoker = SimpleMethodHandle.make(invokerType, lform);
}
invoker = invoker.withInternalMemberName(MemberName.makeMethodHandleInvoke("invoke", mtype));
assert(checkInvoker(invoker));
invoker = makeExactOrGeneralInvoker(false);
generalInvoker = invoker;
return invoker;
}
/*non-public*/ MethodHandle makeBasicInvoker() {
MethodHandle invoker = DirectMethodHandle.make(invokeBasicMethod(targetType));
assert(targetType == targetType.basicType());
// Note: This is not cached here. It is cached by the calling MethodTypeForm.
private MethodHandle makeExactOrGeneralInvoker(boolean isExact) {
MethodType mtype = targetType;
MethodType invokerType = mtype.invokerType();
int which = (isExact ? MethodTypeForm.LF_EX_INVOKER : MethodTypeForm.LF_GEN_INVOKER);
LambdaForm lform = invokeHandleForm(mtype, false, which);
MethodHandle invoker = BoundMethodHandle.bindSingle(invokerType, lform, mtype);
String whichName = (isExact ? "invokeExact" : "invoke");
invoker = invoker.withInternalMemberName(MemberName.makeMethodHandleInvoke(whichName, mtype));
assert(checkInvoker(invoker));
maybeCompileToBytecode(invoker);
return invoker;
}
static MemberName invokeBasicMethod(MethodType type) {
type = type.basicType();
String name = "invokeBasic";
/** If the target type seems to be common enough, eagerly compile the invoker to bytecodes. */
private void maybeCompileToBytecode(MethodHandle invoker) {
final int EAGER_COMPILE_ARITY_LIMIT = 10;
if (targetType == targetType.erase() &&
targetType.parameterCount() < EAGER_COMPILE_ARITY_LIMIT) {
invoker.form.compileToBytecode();
}
}
/*non-public*/ MethodHandle basicInvoker() {
MethodHandle invoker = basicInvoker;
if (invoker != null) return invoker;
MethodType basicType = targetType.basicType();
if (basicType != targetType) {
// double cache; not used significantly
return basicInvoker = basicType.invokers().basicInvoker();
}
MemberName method = invokeBasicMethod(basicType);
invoker = DirectMethodHandle.make(method);
assert(checkInvoker(invoker));
basicInvoker = invoker;
return invoker;
}
// This next one is called from LambdaForm.NamedFunction.<init>.
/*non-public*/ static MemberName invokeBasicMethod(MethodType basicType) {
assert(basicType == basicType.basicType());
try {
//Lookup.findVirtual(MethodHandle.class, name, type);
return IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, MethodHandle.class, name, type);
return IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, MethodHandle.class, "invokeBasic", basicType);
} catch (ReflectiveOperationException ex) {
throw newInternalError("JVM cannot find invoker for "+type, ex);
throw newInternalError("JVM cannot find invoker for "+basicType, ex);
}
}
@ -184,6 +184,7 @@ class Invokers {
vaInvoker = MethodHandles.filterArgument(arrayInvoker, 0, makeSpreader);
}
assert(vaInvoker.type().equals(spreadInvokerType.invokerType()));
maybeCompileToBytecode(vaInvoker);
spreadInvokers[leadingArgCount] = vaInvoker;
return vaInvoker;
}
@ -231,32 +232,38 @@ class Invokers {
return "Invokers"+targetType;
}
static MemberName exactInvokerMethod(MethodType mtype, Object[] appendixResult) {
static MemberName methodHandleInvokeLinkerMethod(String name,
MethodType mtype,
Object[] appendixResult) {
int which;
switch (name) {
case "invokeExact": which = MethodTypeForm.LF_EX_LINKER; break;
case "invoke": which = MethodTypeForm.LF_GEN_LINKER; break;
default: throw new InternalError("not invoker: "+name);
}
LambdaForm lform;
final int MTYPE_ARG_APPENDED = 1; // argument count for appended mtype value
if (mtype.parameterSlotCount() <= MethodType.MAX_MH_ARITY - MTYPE_ARG_APPENDED) {
lform = invokeForm(mtype, false, MethodTypeForm.LF_EX_LINKER);
if (mtype.parameterSlotCount() <= MethodType.MAX_MH_ARITY - MH_LINKER_ARG_APPENDED) {
lform = invokeHandleForm(mtype, false, which);
appendixResult[0] = mtype;
} else {
lform = invokeForm(mtype, true, MethodTypeForm.LF_EX_LINKER);
lform = invokeHandleForm(mtype, true, which);
}
return lform.vmentry;
}
static MemberName genericInvokerMethod(MethodType mtype, Object[] appendixResult) {
LambdaForm lform;
final int MTYPE_ARG_APPENDED = 1; // argument count for appended mtype value
if (mtype.parameterSlotCount() <= MethodType.MAX_MH_ARITY - (MTYPE_ARG_APPENDED + GENERIC_INVOKER_SLOP)) {
lform = invokeForm(mtype, false, MethodTypeForm.LF_GEN_LINKER);
appendixResult[0] = mtype;
prepareForGenericCall(mtype);
} else {
lform = invokeForm(mtype, true, MethodTypeForm.LF_GEN_LINKER);
}
return lform.vmentry;
}
// argument count to account for trailing "appendix value" (typically the mtype)
private static final int MH_LINKER_ARG_APPENDED = 1;
private static LambdaForm invokeForm(MethodType mtype, boolean customized, int which) {
/** Returns an adapter for invokeExact or generic invoke, as a MH or constant pool linker.
* If !customized, caller is responsible for supplying, during adapter execution,
* a copy of the exact mtype. This is because the adapter might be generalized to
* a basic type.
* @param mtype the caller's method type (either basic or full-custom)
* @param customized whether to use a trailing appendix argument (to carry the mtype)
* @param which bit-encoded 0x01 whether it is a CP adapter ("linker") or MHs.invoker value ("invoker");
* 0x02 whether it is for invokeExact or generic invoke
*/
private static LambdaForm invokeHandleForm(MethodType mtype, boolean customized, int which) {
boolean isCached;
if (!customized) {
mtype = mtype.basicType(); // normalize Z to I, String to Object, etc.
@ -301,41 +308,24 @@ class Invokers {
: Arrays.asList(mtype, customized, which, nameCursor, names.length);
if (MTYPE_ARG >= INARG_LIMIT) {
assert(names[MTYPE_ARG] == null);
names[MTYPE_ARG] = BoundMethodHandle.getSpeciesData("L").getterName(names[THIS_MH], 0);
NamedFunction getter = BoundMethodHandle.getSpeciesData("L").getterFunction(0);
names[MTYPE_ARG] = new Name(getter, names[THIS_MH]);
// else if isLinker, then MTYPE is passed in from the caller (e.g., the JVM)
}
// Make the final call. If isGeneric, then prepend the result of type checking.
MethodType outCallType;
Object[] outArgs;
MethodType outCallType = mtype.basicType();
Object[] outArgs = Arrays.copyOfRange(names, CALL_MH, OUTARG_LIMIT, Object[].class);
Object mtypeArg = (customized ? mtype : names[MTYPE_ARG]);
if (!isGeneric) {
names[CHECK_TYPE] = new Name(NF_checkExactType, names[CALL_MH], mtypeArg);
// mh.invokeExact(a*):R => checkExactType(mh, TYPEOF(a*:R)); mh.invokeBasic(a*)
outArgs = Arrays.copyOfRange(names, CALL_MH, OUTARG_LIMIT, Object[].class);
outCallType = mtype;
} else if (customized) {
names[CHECK_TYPE] = new Name(NF_asType, names[CALL_MH], mtypeArg);
// mh.invokeGeneric(a*):R =>
// let mt=TYPEOF(a*:R), tmh=asType(mh, mt);
// tmh.invokeBasic(a*)
outArgs = Arrays.copyOfRange(names, CALL_MH, OUTARG_LIMIT, Object[].class);
outCallType = mtype;
} else {
names[CHECK_TYPE] = new Name(NF_checkGenericType, names[CALL_MH], mtypeArg);
// mh.invokeGeneric(a*):R =>
// let mt=TYPEOF(a*:R), gamh=checkGenericType(mh, mt);
// gamh.invokeBasic(mt, mh, a*)
final int PREPEND_GAMH = 0, PREPEND_MT = 1, PREPEND_COUNT = 2;
assert(GENERIC_INVOKER_SLOP == PREPEND_COUNT);
outArgs = Arrays.copyOfRange(names, CALL_MH, OUTARG_LIMIT + PREPEND_COUNT, Object[].class);
// prepend arguments:
System.arraycopy(outArgs, 0, outArgs, PREPEND_COUNT, outArgs.length - PREPEND_COUNT);
outArgs[PREPEND_GAMH] = names[CHECK_TYPE];
outArgs[PREPEND_MT] = mtypeArg;
outCallType = mtype.insertParameterTypes(0, MethodType.class, MethodHandle.class);
// mh.invokeGeneric(a*):R => checkGenericType(mh, TYPEOF(a*:R)).invokeBasic(a*)
outArgs[0] = names[CHECK_TYPE];
}
names[LINKER_CALL] = new Name(invokeBasicMethod(outCallType), outArgs);
names[LINKER_CALL] = new Name(outCallType, outArgs);
lform = new LambdaForm(debugName, INARG_LIMIT, names);
if (isLinker)
lform.compileToBytecode(); // JVM needs a real methodOop
@ -343,7 +333,6 @@ class Invokers {
lform = mtype.form().setCachedLambdaForm(which, lform);
return lform;
}
private static final int GENERIC_INVOKER_SLOP = 2; // used elsewhere to avoid arity problems
/*non-public*/ static
WrongMethodTypeException newWrongMethodTypeException(MethodType actual, MethodType expected) {
@ -362,47 +351,53 @@ class Invokers {
throw newWrongMethodTypeException(expected, actual);
}
/** Static definition of MethodHandle.invokeGeneric checking code. */
/** Static definition of MethodHandle.invokeGeneric checking code.
* Directly returns the type-adjusted MH to invoke, as follows:
* {@code (R)MH.invoke(a*) => MH.asType(TYPEOF(a*:R)).invokeBasic(a*)}
*/
/*non-public*/ static
@ForceInline
Object checkGenericType(Object mhObj, Object expectedObj) {
MethodHandle mh = (MethodHandle) mhObj;
MethodType expected = (MethodType) expectedObj;
//MethodType actual = mh.type();
MethodHandle gamh = expected.form().genericInvoker;
if (gamh != null) return gamh;
return prepareForGenericCall(expected);
}
/**
* Returns an adapter GA for invoking a MH with type adjustments.
* The MethodType of the generic invocation site is prepended to MH
* and its arguments as follows:
* {@code (R)MH.invoke(A*) => GA.invokeBasic(TYPEOF<A*,R>, MH, A*)}
*/
/*non-public*/ static MethodHandle prepareForGenericCall(MethodType mtype) {
// force any needed adapters to be preconstructed
MethodTypeForm form = mtype.form();
MethodHandle gamh = form.genericInvoker;
if (gamh != null) return gamh;
try {
// Trigger adapter creation.
gamh = InvokeGeneric.generalInvokerOf(form.erasedType);
form.genericInvoker = gamh;
return gamh;
} catch (Exception ex) {
throw newInternalError("Exception while resolving inexact invoke", ex);
}
if (mh.type() == expected) return mh;
MethodHandle atc = mh.asTypeCache;
if (atc != null && atc.type() == expected) return atc;
return mh.asType(expected);
/* Maybe add more paths here. Possible optimizations:
* for (R)MH.invoke(a*),
* let MT0 = TYPEOF(a*:R), MT1 = MH.type
*
* if MT0==MT1 or MT1 can be safely called by MT0
* => MH.invokeBasic(a*)
* if MT1 can be safely called by MT0[R := Object]
* => MH.invokeBasic(a*) & checkcast(R)
* if MT1 can be safely called by MT0[* := Object]
* => checkcast(A)* & MH.invokeBasic(a*) & checkcast(R)
* if a big adapter BA can be pulled out of (MT0,MT1)
* => BA.invokeBasic(MT0,MH,a*)
* if a local adapter LA can cached on static CS0 = new GICS(MT0)
* => CS0.LA.invokeBasic(MH,a*)
* else
* => MH.asType(MT0).invokeBasic(A*)
*/
}
static MemberName linkToCallSiteMethod(MethodType mtype) {
LambdaForm lform = callSiteForm(mtype);
LambdaForm lform = callSiteForm(mtype, false);
return lform.vmentry;
}
private static LambdaForm callSiteForm(MethodType mtype) {
static MemberName linkToTargetMethod(MethodType mtype) {
LambdaForm lform = callSiteForm(mtype, true);
return lform.vmentry;
}
// skipCallSite is true if we are optimizing a ConstantCallSite
private static LambdaForm callSiteForm(MethodType mtype, boolean skipCallSite) {
mtype = mtype.basicType(); // normalize Z to I, String to Object, etc.
LambdaForm lform = mtype.form().cachedLambdaForm(MethodTypeForm.LF_CS_LINKER);
final int which = (skipCallSite ? MethodTypeForm.LF_MH_LINKER : MethodTypeForm.LF_CS_LINKER);
LambdaForm lform = mtype.form().cachedLambdaForm(which);
if (lform != null) return lform;
// exactInvokerForm (Object,Object)Object
// link with java.lang.invoke.MethodHandle.invokeBasic(MethodHandle,Object,Object)Object/invokeSpecial
@ -410,24 +405,26 @@ class Invokers {
final int OUTARG_LIMIT = ARG_BASE + mtype.parameterCount();
final int INARG_LIMIT = OUTARG_LIMIT + 1;
int nameCursor = OUTARG_LIMIT;
final int CSITE_ARG = nameCursor++; // the last in-argument
final int CALL_MH = nameCursor++; // result of getTarget
final int APPENDIX_ARG = nameCursor++; // the last in-argument
final int CSITE_ARG = skipCallSite ? -1 : APPENDIX_ARG;
final int CALL_MH = skipCallSite ? APPENDIX_ARG : nameCursor++; // result of getTarget
final int LINKER_CALL = nameCursor++;
MethodType invokerFormType = mtype.appendParameterTypes(CallSite.class);
MethodType invokerFormType = mtype.appendParameterTypes(skipCallSite ? MethodHandle.class : CallSite.class);
Name[] names = arguments(nameCursor - INARG_LIMIT, invokerFormType);
assert(names.length == nameCursor);
assert(names[CSITE_ARG] != null);
names[CALL_MH] = new Name(NF_getCallSiteTarget, names[CSITE_ARG]);
assert(names[APPENDIX_ARG] != null);
if (!skipCallSite)
names[CALL_MH] = new Name(NF_getCallSiteTarget, names[CSITE_ARG]);
// (site.)invokedynamic(a*):R => mh = site.getTarget(); mh.invokeBasic(a*)
final int PREPEND_MH = 0, PREPEND_COUNT = 1;
Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, OUTARG_LIMIT + PREPEND_COUNT, Object[].class);
// prepend MH argument:
System.arraycopy(outArgs, 0, outArgs, PREPEND_COUNT, outArgs.length - PREPEND_COUNT);
outArgs[PREPEND_MH] = names[CALL_MH];
names[LINKER_CALL] = new Name(invokeBasicMethod(mtype), outArgs);
lform = new LambdaForm("linkToCallSite", INARG_LIMIT, names);
names[LINKER_CALL] = new Name(mtype, outArgs);
lform = new LambdaForm((skipCallSite ? "linkToTargetMethod" : "linkToCallSite"), INARG_LIMIT, names);
lform.compileToBytecode(); // JVM needs a real methodOop
lform = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_CS_LINKER, lform);
lform = mtype.form().setCachedLambdaForm(which, lform);
return lform;
}

31
jdk/src/share/classes/java/lang/invoke/LambdaForm.java

@ -457,7 +457,7 @@ class LambdaForm {
isCompiled = true;
return vmentry;
} catch (Error | Exception ex) {
throw newInternalError(this.toString(), ex);
throw newInternalError("compileToBytecode", ex);
}
}
@ -683,8 +683,9 @@ class LambdaForm {
*/
static void traceInterpreter(String event, Object obj, Object... args) {
if (!TRACE_INTERPRETER) return;
System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
if (TRACE_INTERPRETER) {
System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
}
}
static void traceInterpreter(String event, Object obj) {
traceInterpreter(event, obj, (Object[])null);
@ -982,6 +983,16 @@ class LambdaForm {
//resolvedHandle = eraseSubwordTypes(resolvedHandle);
this.resolvedHandle = resolvedHandle;
}
NamedFunction(MethodType basicInvokerType) {
assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
this.member = resolvedHandle.internalMemberName();
} else {
// necessary to pass BigArityTest
this.member = Invokers.invokeBasicMethod(basicInvokerType);
}
}
// The next 3 constructors are used to break circular dependencies on MH.invokeStatic, etc.
// Any LambdaForm containing such a member is not interpretable.
@ -1229,7 +1240,7 @@ class LambdaForm {
}
public String toString() {
if (member == null) return resolvedHandle.toString();
if (member == null) return String.valueOf(resolvedHandle);
return member.getDeclaringClass().getSimpleName()+"."+member.getName();
}
}
@ -1279,6 +1290,10 @@ class LambdaForm {
Name(MethodHandle function, Object... arguments) {
this(new NamedFunction(function), arguments);
}
Name(MethodType functionType, Object... arguments) {
this(new NamedFunction(functionType), arguments);
assert(arguments[0] instanceof Name && ((Name)arguments[0]).type == 'L');
}
Name(MemberName function, Object... arguments) {
this(new NamedFunction(function), arguments);
}
@ -1622,4 +1637,12 @@ class LambdaForm {
*/
static { NamedFunction.initializeInvokers(); }
// The following hack is necessary in order to suppress TRACE_INTERPRETER
// during execution of the static initializes of this class.
// Turning on TRACE_INTERPRETER too early will cause
// stack overflows and other misbehavior during attempts to trace events
// that occur during LambdaForm.<clinit>.
// Therefore, do not move this line higher in this file, and do not remove.
private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
}

75
jdk/src/share/classes/java/lang/invoke/MemberName.java

@ -556,6 +556,9 @@ import java.util.Objects;
}
throw new IllegalArgumentException(this.toString());
}
/** If this MN is not REF_newInvokeSpecial, return a clone with that ref. kind.
* In that case it must already be REF_invokeSpecial.
*/
public MemberName asConstructor() {
switch (getReferenceKind()) {
case REF_invokeSpecial: return clone().changeReferenceKind(REF_newInvokeSpecial, REF_invokeSpecial);
@ -563,6 +566,32 @@ import java.util.Objects;
}
throw new IllegalArgumentException(this.toString());
}
/** If this MN is a REF_invokeSpecial, return a clone with the "normal" kind
* REF_invokeVirtual; also switch either to REF_invokeInterface if clazz.isInterface.
* The end result is to get a fully virtualized version of the MN.
* (Note that resolving in the JVM will sometimes devirtualize, changing
* REF_invokeVirtual of a final to REF_invokeSpecial, and REF_invokeInterface
* in some corner cases to either of the previous two; this transform
* undoes that change under the assumption that it occurred.)
*/
public MemberName asNormalOriginal() {
byte normalVirtual = clazz.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
byte refKind = getReferenceKind();
byte newRefKind = refKind;
MemberName result = this;
switch (refKind) {
case REF_invokeInterface:
case REF_invokeVirtual:
case REF_invokeSpecial:
newRefKind = normalVirtual;
break;
}
if (newRefKind == refKind)
return this;
result = clone().changeReferenceKind(newRefKind, refKind);
assert(this.referenceKindIsConsistentWith(result.getReferenceKind()));
return result;
}
/** Create a name for the given reflected constructor. The resulting name will be in a resolved state. */
@SuppressWarnings("LeakingThisInConstructor")
public MemberName(Constructor<?> ctor) {
@ -660,7 +689,7 @@ import java.util.Objects;
@Override
public int hashCode() {
return Objects.hash(clazz, flags, name, getType());
return Objects.hash(clazz, getReferenceKind(), name, getType());
}
@Override
public boolean equals(Object that) {
@ -676,13 +705,14 @@ import java.util.Objects;
if (this == that) return true;
if (that == null) return false;
return this.clazz == that.clazz
&& this.flags == that.flags
&& this.getReferenceKind() == that.getReferenceKind()
&& Objects.equals(this.name, that.name)
&& Objects.equals(this.getType(), that.getType());
}
// Construction from symbolic parts, for queries:
/** Create a field or type name from the given components: Declaring class, name, type, reference kind.
/** Create a field or type name from the given components:
* Declaring class, name, type, reference kind.
* The declaring class may be supplied as null if this is to be a bare name and type.
* The resulting name will in an unresolved state.
*/
@ -706,21 +736,34 @@ import java.util.Objects;
* The resulting name will in an unresolved state.
*/
public MemberName(Class<?> defClass, String name, MethodType type, byte refKind) {
@SuppressWarnings("LocalVariableHidesMemberVariable")
int flags = (name != null && name.equals(CONSTRUCTOR_NAME) ? IS_CONSTRUCTOR : IS_METHOD);
init(defClass, name, type, flagsMods(flags, 0, refKind));
int initFlags = (name != null && name.equals(CONSTRUCTOR_NAME) ? IS_CONSTRUCTOR : IS_METHOD);
init(defClass, name, type, flagsMods(initFlags, 0, refKind));
initResolved(false);
}
/** Create a method, constructor, or field name from the given components:
* Reference kind, declaring class, name, type.
*/
public MemberName(byte refKind, Class<?> defClass, String name, Object type) {
int kindFlags;
if (MethodHandleNatives.refKindIsField(refKind)) {
kindFlags = IS_FIELD;
if (!(type instanceof Class))
throw newIllegalArgumentException("not a field type");
} else if (MethodHandleNatives.refKindIsMethod(refKind)) {
kindFlags = IS_METHOD;
if (!(type instanceof MethodType))
throw newIllegalArgumentException("not a method type");
} else if (refKind == REF_newInvokeSpecial) {
kindFlags = IS_CONSTRUCTOR;
if (!(type instanceof MethodType) ||
!CONSTRUCTOR_NAME.equals(name))
throw newIllegalArgumentException("not a constructor type or name");
} else {
throw newIllegalArgumentException("bad reference kind "+refKind);
}
init(defClass, name, type, flagsMods(kindFlags, 0, refKind));
initResolved(false);
}
// /** Create a method or constructor name from the given components: Declaring class, name, type, modifiers.
// * It will be a constructor if and only if the name is {@code "&lt;init&gt;"}.
// * The declaring class may be supplied as null if this is to be a bare name and type.
// * The modifier flags default to zero.
// * The resulting name will in an unresolved state.
// */
// public MemberName(Class<?> defClass, String name, MethodType type, Void unused) {
// this(defClass, name, type, REF_NONE);
// }
/** Query whether this member name is resolved to a non-static, non-final method.
*/
public boolean hasReceiverTypeDispatch() {

22
jdk/src/share/classes/java/lang/invoke/MethodHandle.java

@ -420,6 +420,8 @@ public abstract class MethodHandle {
private final MethodType type;
/*private*/ final LambdaForm form;
// form is not private so that invokers can easily fetch it
/*private*/ MethodHandle asTypeCache;
// asTypeCache is not private so that invokers can easily fetch it
/**
* Reports the type of this method handle.
@ -739,10 +741,24 @@ public abstract class MethodHandle {
* @see MethodHandles#explicitCastArguments
*/
public MethodHandle asType(MethodType newType) {
if (!type.isConvertibleTo(newType)) {
throw new WrongMethodTypeException("cannot convert "+this+" to "+newType);
// Fast path alternative to a heavyweight {@code asType} call.
// Return 'this' if the conversion will be a no-op.
if (newType == type) {
return this;
}
return convertArguments(newType);
// Return 'this.asTypeCache' if the conversion is already memoized.
MethodHandle atc = asTypeCache;
if (atc != null && newType == atc.type) {
return atc;
}
return asTypeUncached(newType);
}
/** Override this to change asType behavior. */
/*non-public*/ MethodHandle asTypeUncached(MethodType newType) {
if (!type.isConvertibleTo(newType))
throw new WrongMethodTypeException("cannot convert "+this+" to "+newType);
return asTypeCache = convertArguments(newType);
}
/**

23
jdk/src/share/classes/java/lang/invoke/MethodHandleImpl.java

@ -314,13 +314,13 @@ import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
static class AsVarargsCollector extends MethodHandle {
private final MethodHandle target;
private final Class<?> arrayType;
private MethodHandle cache;
private /*@Stable*/ MethodHandle asCollectorCache;
AsVarargsCollector(MethodHandle target, MethodType type, Class<?> arrayType) {
super(type, reinvokerForm(target));
this.target = target;
this.arrayType = arrayType;
this.cache = target.asCollector(arrayType, 0);
this.asCollectorCache = target.asCollector(arrayType, 0);
}
@Override MethodHandle reinvokerTarget() { return target; }
@ -336,18 +336,19 @@ import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
}
@Override
public MethodHandle asType(MethodType newType) {
public MethodHandle asTypeUncached(MethodType newType) {
MethodType type = this.type();
int collectArg = type.parameterCount() - 1;
int newArity = newType.parameterCount();
if (newArity == collectArg+1 &&
type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
// if arity and trailing parameter are compatible, do normal thing
return asFixedArity().asType(newType);
return asTypeCache = asFixedArity().asType(newType);
}
// check cache
if (cache.type().parameterCount() == newArity)
return cache.asType(newType);
MethodHandle acc = asCollectorCache;
if (acc != null && acc.type().parameterCount() == newArity)
return asTypeCache = acc.asType(newType);
// build and cache a collector
int arrayLength = newArity - collectArg;
MethodHandle collector;
@ -357,8 +358,8 @@ import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
} catch (IllegalArgumentException ex) {
throw new WrongMethodTypeException("cannot build collector", ex);
}
cache = collector;
return collector.asType(newType);
asCollectorCache = collector;
return asTypeCache = collector.asType(newType);
}
@Override
@ -977,6 +978,12 @@ import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
return target;
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
// This MH is an alias for target, except for the MemberName
// Drop the MemberName if there is any conversion.
return asTypeCache = target.asType(newType);
}
@Override
MemberName internalMemberName() {
return member;
}

42
jdk/src/share/classes/java/lang/invoke/MethodHandleNatives.java

@ -233,20 +233,19 @@ class MethodHandleNatives {
}
static String refKindName(byte refKind) {
assert(refKindIsValid(refKind));
return REFERENCE_KIND_NAME[refKind];
switch (refKind) {
case REF_getField: return "getField";
case REF_getStatic: return "getStatic";
case REF_putField: return "putField";
case REF_putStatic: return "putStatic";
case REF_invokeVirtual: return "invokeVirtual";
case REF_invokeStatic: return "invokeStatic";
case REF_invokeSpecial: return "invokeSpecial";
case REF_newInvokeSpecial: return "newInvokeSpecial";
case REF_invokeInterface: return "invokeInterface";
default: return "REF_???";
}
}
private static String[] REFERENCE_KIND_NAME = {
null,
"getField",
"getStatic",
"putField",
"putStatic",
"invokeVirtual",
"invokeStatic",
"invokeSpecial",
"newInvokeSpecial",
"invokeInterface"
};
private static native int getNamedCon(int which, Object[] name);
static boolean verifyConstants() {
@ -294,12 +293,18 @@ class MethodHandleNatives {
Class<?> caller = (Class<?>)callerObj;
String name = nameObj.toString().intern();
MethodType type = (MethodType)typeObj;
appendixResult[0] = CallSite.makeSite(bootstrapMethod,
CallSite callSite = CallSite.makeSite(bootstrapMethod,
name,
type,
staticArguments,
caller);
return Invokers.linkToCallSiteMethod(type);
if (callSite instanceof ConstantCallSite) {
appendixResult[0] = callSite.dynamicInvoker();
return Invokers.linkToTargetMethod(type);
} else {
appendixResult[0] = callSite;
return Invokers.linkToCallSiteMethod(type);
}
}
/**
@ -388,12 +393,7 @@ class MethodHandleNatives {
Object[] appendixResult) {
try {
if (defc == MethodHandle.class && refKind == REF_invokeVirtual) {
switch (name) {
case "invoke":
return Invokers.genericInvokerMethod(fixMethodType(callerClass, type), appendixResult);
case "invokeExact":
return Invokers.exactInvokerMethod(fixMethodType(callerClass, type), appendixResult);
}
return Invokers.methodHandleInvokeLinkerMethod(name, fixMethodType(callerClass, type), appendixResult);
}
} catch (Throwable ex) {
if (ex instanceof LinkageError)

93
jdk/src/share/classes/java/lang/invoke/MethodHandles.java

@ -39,6 +39,7 @@ import sun.reflect.misc.ReflectUtil;
import sun.security.util.SecurityConstants;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandleNatives.Constants.*;
import java.util.concurrent.ConcurrentHashMap;
import sun.security.util.SecurityConstants;
/**
@ -1090,19 +1091,30 @@ return mh1;
MemberName resolveOrFail(byte refKind, Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
checkSymbolicClass(refc); // do this before attempting to resolve
name.getClass(); type.getClass(); // NPE
name.getClass(); // NPE
type.getClass(); // NPE
return IMPL_NAMES.resolveOrFail(refKind, new MemberName(refc, name, type, refKind), lookupClassOrNull(),
NoSuchFieldException.class);
}
MemberName resolveOrFail(byte refKind, Class<?> refc, String name, MethodType type) throws NoSuchMethodException, IllegalAccessException {
checkSymbolicClass(refc); // do this before attempting to resolve
name.getClass(); type.getClass(); // NPE
name.getClass(); // NPE
type.getClass(); // NPE
return IMPL_NAMES.resolveOrFail(refKind, new MemberName(refc, name, type, refKind), lookupClassOrNull(),
NoSuchMethodException.class);
}
MemberName resolveOrFail(byte refKind, MemberName member) throws ReflectiveOperationException {
checkSymbolicClass(member.getDeclaringClass()); // do this before attempting to resolve
member.getName().getClass(); // NPE
member.getType().getClass(); // NPE
return IMPL_NAMES.resolveOrFail(refKind, member, lookupClassOrNull(),
ReflectiveOperationException.class);
}
void checkSymbolicClass(Class<?> refc) throws IllegalAccessException {
refc.getClass(); // NPE
Class<?> caller = lookupClassOrNull();
if (caller != null && !VerifyAccess.isClassAccessible(refc, caller, allowedModes))
throw new MemberName(refc).makeAccessException("symbolic reference class is not public", this);
@ -1348,29 +1360,74 @@ return mh1;
*/
/*non-public*/
MethodHandle linkMethodHandleConstant(byte refKind, Class<?> defc, String name, Object type) throws ReflectiveOperationException {
MemberName resolved = null;
if (type instanceof MemberName) {
resolved = (MemberName) type;
if (!resolved.isResolved()) throw new InternalError("unresolved MemberName");
assert(name == null || name.equals(resolved.getName()));
if (!(type instanceof Class || type instanceof MethodType))
throw new InternalError("unresolved MemberName");
MemberName member = new MemberName(refKind, defc, name, type);
MethodHandle mh = LOOKASIDE_TABLE.get(member);
if (mh != null) {
checkSymbolicClass(defc);
return mh;
}
MemberName resolved = resolveOrFail(refKind, member);
mh = getDirectMethodHandle(refKind, defc, resolved);
if (mh instanceof DirectMethodHandle
&& canBeCached(refKind, defc, resolved)) {
MemberName key = mh.internalMemberName();
if (key != null) {
key = key.asNormalOriginal();
}
if (member.equals(key)) { // better safe than sorry
LOOKASIDE_TABLE.put(key, (DirectMethodHandle) mh);
}
}
return mh;
}
private
boolean canBeCached(byte refKind, Class<?> defc, MemberName member) {
if (refKind == REF_invokeSpecial) {
return false;
}
if (!Modifier.isPublic(defc.getModifiers()) ||
!Modifier.isPublic(member.getDeclaringClass().getModifiers()) ||
!member.isPublic() ||
member.isCallerSensitive()) {
return false;
}
ClassLoader loader = defc.getClassLoader();
if (!sun.misc.VM.isSystemDomainLoader(loader)) {
ClassLoader sysl = ClassLoader.getSystemClassLoader();
boolean found = false;
while (sysl != null) {
if (loader == sysl) { found = true; break; }
sysl = sysl.getParent();
}
if (!found) {
return false;
}
}
try {
MemberName resolved2 = publicLookup().resolveOrFail(refKind,
new MemberName(refKind, defc, member.getName(), member.getType()));
checkSecurityManager(defc, resolved2);
} catch (ReflectiveOperationException | SecurityException ex) {
return false;
}
return true;
}
private
MethodHandle getDirectMethodHandle(byte refKind, Class<?> defc, MemberName member) throws ReflectiveOperationException {
if (MethodHandleNatives.refKindIsField(refKind)) {
MemberName field = (resolved != null) ? resolved
: resolveOrFail(refKind, defc, name, (Class<?>) type);
return getDirectField(refKind, defc, field);
return getDirectField(refKind, defc, member);
} else if (MethodHandleNatives.refKindIsMethod(refKind)) {
MemberName method = (resolved != null) ? resolved
: resolveOrFail(refKind, defc, name, (MethodType) type);
return getDirectMethod(refKind, defc, method, lookupClass);
return getDirectMethod(refKind, defc, member, lookupClass);
} else if (refKind == REF_newInvokeSpecial) {
assert(name == null || name.equals("<init>"));
MemberName ctor = (resolved != null) ? resolved
: resolveOrFail(REF_newInvokeSpecial, defc, name, (MethodType) type);
return getDirectConstructor(defc, ctor);
return getDirectConstructor(defc, member);
}
// oops
throw new ReflectiveOperationException("bad MethodHandle constant #"+refKind+" "+name+" : "+type);
throw newIllegalArgumentException("bad MethodHandle constant #"+member);
}
static ConcurrentHashMap<MemberName, DirectMethodHandle> LOOKASIDE_TABLE = new ConcurrentHashMap<>();
}
/**

19
jdk/src/share/classes/java/lang/invoke/MethodTypeForm.java

@ -28,6 +28,7 @@ package java.lang.invoke;
import sun.invoke.util.Wrapper;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandleNatives.Constants.*;
import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
/**
* Shared information for a group of method types, which differ
@ -74,7 +75,8 @@ final class MethodTypeForm {
LF_GEN_LINKER = 11,
LF_GEN_INVOKER = 12,
LF_CS_LINKER = 13, // linkToCallSite_CS
LF_LIMIT = 14;
LF_MH_LINKER = 14, // linkToCallSite_MH
LF_LIMIT = 15;
public MethodType erasedType() {
return erasedType;
@ -97,11 +99,24 @@ final class MethodTypeForm {
assert(erasedType == basicType) : "erasedType: " + erasedType + " != basicType: " + basicType; // primitives must be flattened also
MethodHandle invoker = basicInvoker;
if (invoker != null) return invoker;
invoker = basicType.invokers().makeBasicInvoker();
invoker = DirectMethodHandle.make(invokeBasicMethod(basicType));
basicInvoker = invoker;
return invoker;
}
// This next one is called from LambdaForm.NamedFunction.<init>.
/*non-public*/ static MemberName invokeBasicMethod(MethodType basicType) {
assert(basicType == basicType.basicType());
try {
// Do approximately the same as this public API call:
// Lookup.findVirtual(MethodHandle.class, name, type);
// But bypass access and corner case checks, since we know exactly what we need.
return IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, MethodHandle.class, "invokeBasic", basicType);
} catch (ReflectiveOperationException ex) {
throw newInternalError("JVM cannot find invoker for "+basicType, ex);
}
}
/**
* Build an MTF for a given type, which must have all references erased to Object.
* This MTF will stand for that type and all un-erased variations.