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8185993: MethodHandle.invokeWithArguments jumbo-arity

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Reviewed-by: psandoz, vlivanov
This commit is contained in:
John R Rose 2017-09-22 15:28:16 -07:00
parent 71e91d9c2e
commit f98aab0db9
6 changed files with 294 additions and 46 deletions
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49
src/java.base/share/classes/java/lang/invoke/MethodHandleImpl.java
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@ -523,6 +523,12 @@ import static jdk.internal.org.objectweb.asm.Opcodes.*;
return asFixedArity();
}
@Override
public MethodHandle withVarargs(boolean makeVarargs) {
if (makeVarargs) return this;
return asFixedArity();
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
MethodType type = this.type();
@ -561,6 +567,49 @@ import static jdk.internal.org.objectweb.asm.Opcodes.*;
: Arrays.asList(this, newType);
return true;
}
@Override
public Object invokeWithArguments(Object... arguments) throws Throwable {
MethodType type = this.type();
int argc;
final int MAX_SAFE = 127; // 127 longs require 254 slots, which is safe to spread
if (arguments == null
|| (argc = arguments.length) <= MAX_SAFE
|| argc < type.parameterCount()) {
return super.invokeWithArguments(arguments);
}
// a jumbo invocation requires more explicit reboxing of the trailing arguments
int uncollected = type.parameterCount() - 1;
Class<?> elemType = arrayType.getComponentType();
int collected = argc - uncollected;
Object collArgs = (elemType == Object.class)
? new Object[collected] : Array.newInstance(elemType, collected);
if (!elemType.isPrimitive()) {
// simple cast: just do some casting
try {
System.arraycopy(arguments, uncollected, collArgs, 0, collected);
} catch (ArrayStoreException ex) {
return super.invokeWithArguments(arguments);
}
} else {
// corner case of flat array requires reflection (or specialized copy loop)
MethodHandle arraySetter = MethodHandles.arrayElementSetter(arrayType);
try {
for (int i = 0; i < collected; i++) {
arraySetter.invoke(collArgs, i, arguments[uncollected + i]);
}
} catch (WrongMethodTypeException|ClassCastException ex) {
return super.invokeWithArguments(arguments);
}
}
// chop the jumbo list down to size and call in non-varargs mode
Object[] newArgs = new Object[uncollected + 1];
System.arraycopy(arguments, 0, newArgs, 0, uncollected);
newArgs[uncollected] = collArgs;
return asFixedArity().invokeWithArguments(newArgs);
}
}
/** Factory method: Spread selected argument. */