/*
* Copyright (c) 2008, 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
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package java.lang.invoke;
import sun.invoke.util.Wrapper;
import static java.lang.invoke.MethodHandleStatics.*;
/**
* Shared information for a group of method types, which differ
* only by reference types, and therefore share a common erasure
* and wrapping.
* <p>
* For an empirical discussion of the structure of method types,
* see <a href="http://groups.google.com/group/jvm-languages/browse_thread/thread/ac9308ae74da9b7e/">
* the thread "Avoiding Boxing" on jvm-languages</a>.
* There are approximately 2000 distinct erased method types in the JDK.
* There are a little over 10 times that number of unerased types.
* No more than half of these are likely to be loaded at once.
* @author John Rose
*/
class MethodTypeForm {
final int[] argToSlotTable, slotToArgTable;
final long argCounts; // packed slot & value counts
final long primCounts; // packed prim & double counts
final int vmslots; // total number of parameter slots
private Object vmlayout; // vm-specific information for calls
final MethodType erasedType; // the canonical erasure
/*lazy*/ MethodType primsAsBoxes; // replace prims by wrappers
/*lazy*/ MethodType primArgsAsBoxes; // wrap args only; make raw return
/*lazy*/ MethodType primsAsInts; // replace prims by int/long
/*lazy*/ MethodType primsAsLongs; // replace prims by long
/*lazy*/ MethodType primsAtEnd; // reorder primitives to the end
// Cached adapter information:
/*lazy*/ ToGeneric toGeneric; // convert cs. with prims to w/o
/*lazy*/ FromGeneric fromGeneric; // convert cs. w/o prims to with
/*lazy*/ SpreadGeneric[] spreadGeneric; // expand one argument to many
/*lazy*/ FilterGeneric filterGeneric; // convert argument(s) on the fly
/*lazy*/ MethodHandle genericInvoker; // hook for inexact invoke
public MethodType erasedType() {
return erasedType;
}
protected MethodTypeForm(MethodType erasedType) {
this.erasedType = erasedType;
Class<?>[] ptypes = erasedType.ptypes();
int ptypeCount = ptypes.length;
int pslotCount = ptypeCount; // temp. estimate
int rtypeCount = 1; // temp. estimate
int rslotCount = 1; // temp. estimate
int[] argToSlotTab = null, slotToArgTab = null;
// Walk the argument types, looking for primitives.
int pac = 0, lac = 0, prc = 0, lrc = 0;
Class<?> epts[] = ptypes;
for (int i = 0; i < epts.length; i++) {
Class<?> pt = epts[i];
if (pt != Object.class) {
assert(pt.isPrimitive());
++pac;
if (hasTwoArgSlots(pt)) ++lac;
}
}
pslotCount += lac; // #slots = #args + #longs
Class<?> rt = erasedType.returnType();
if (rt != Object.class) {
++prc; // even void.class counts as a prim here
if (hasTwoArgSlots(rt)) ++lrc;
// adjust #slots, #args
if (rt == void.class)
rtypeCount = rslotCount = 0;
else
rslotCount += lrc;
}
if (lac != 0) {
int slot = ptypeCount + lac;
slotToArgTab = new int[slot+1];
argToSlotTab = new int[1+ptypeCount];
argToSlotTab[0] = slot; // argument "-1" is past end of slots
for (int i = 0; i < epts.length; i++) {
Class<?> pt = epts[i];
if (hasTwoArgSlots(pt)) --slot;
--slot;
slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note
argToSlotTab[1+i] = slot;
}
assert(slot == 0); // filled the table
}
this.primCounts = pack(lrc, prc, lac, pac);
this.argCounts = pack(rslotCount, rtypeCount, pslotCount, ptypeCount);
if (slotToArgTab == null) {
int slot = ptypeCount; // first arg is deepest in stack
slotToArgTab = new int[slot+1];
argToSlotTab = new int[1+ptypeCount];
argToSlotTab[0] = slot; // argument "-1" is past end of slots
for (int i = 0; i < ptypeCount; i++) {
--slot;
slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note
argToSlotTab[1+i] = slot;
}
}
this.argToSlotTable = argToSlotTab;
this.slotToArgTable = slotToArgTab;
if (pslotCount >= 256) throw newIllegalArgumentException("too many arguments");
// send a few bits down to the JVM:
this.vmslots = parameterSlotCount();
// short circuit some no-op canonicalizations:
if (!hasPrimitives()) {
primsAsBoxes = erasedType;
primArgsAsBoxes = erasedType;
primsAsInts = erasedType;
primsAsLongs = erasedType;
primsAtEnd = erasedType;
}
}
/** Turn all primitive types to corresponding wrapper types.
*/
public MethodType primsAsBoxes() {
MethodType ct = primsAsBoxes;
if (ct != null) return ct;
MethodType t = erasedType;
ct = canonicalize(erasedType, WRAP, WRAP);
if (ct == null) ct = t; // no prims to box
return primsAsBoxes = ct;
}
/** Turn all primitive argument types to corresponding wrapper types.
* Subword and void return types are promoted to int.
*/
public MethodType primArgsAsBoxes() {
MethodType ct = primArgsAsBoxes;
if (ct != null) return ct;
MethodType t = erasedType;
ct = canonicalize(erasedType, RAW_RETURN, WRAP);
if (ct == null) ct = t; // no prims to box
return primArgsAsBoxes = ct;
}
/** Turn all primitive types to either int or long.
* Floating point return types are not changed, because
* they may require special calling sequences.
* A void return value is turned to int.
*/
public MethodType primsAsInts() {
MethodType ct = primsAsInts;
if (ct != null) return ct;
MethodType t = erasedType;
ct = canonicalize(t, RAW_RETURN, INTS);
if (ct == null) ct = t; // no prims to int-ify
return primsAsInts = ct;
}
/** Turn all primitive types to either int or long.
* Floating point return types are not changed, because
* they may require special calling sequences.
* A void return value is turned to int.
*/
public MethodType primsAsLongs() {
MethodType ct = primsAsLongs;
if (ct != null) return ct;
MethodType t = erasedType;
ct = canonicalize(t, RAW_RETURN, LONGS);
if (ct == null) ct = t; // no prims to int-ify
return primsAsLongs = ct;
}
/** Stably sort parameters into 3 buckets: ref, int, long. */
public MethodType primsAtEnd() {
MethodType ct = primsAtEnd;
if (ct != null) return ct;
MethodType t = erasedType;
int pac = primitiveParameterCount();
if (pac == 0)
return primsAtEnd = t;
int argc = parameterCount();
int lac = longPrimitiveParameterCount();
if (pac == argc && (lac == 0 || lac == argc))
return primsAtEnd = t;
// known to have a mix of 2 or 3 of ref, int, long
int[] reorder = primsAtEndOrder(t);
ct = reorderParameters(t, reorder, null);
//System.out.println("t="+t+" / reorder="+java.util.Arrays.toString(reorder)+" => "+ct);
return primsAtEnd = ct;
}
/** Compute a new ordering of parameters so that all references
* are before all ints or longs, and all ints are before all longs.
* For this ordering, doubles count as longs, and all other primitive
* values count as ints.
* As a special case, if the parameters are already in the specified
* order, this method returns a null reference, rather than an array
* specifying a null permutation.
* <p>
* For example, the type {@code (int,boolean,int,Object,String)void}
* produces the order {@code {3,4,0,1,2}}, the type
* {@code (long,int,String)void} produces {@code {2,1,2}}, and
* the type {@code (Object,int)Object} produces {@code null}.
*/
public static int[] primsAtEndOrder(MethodType mt) {
MethodTypeForm form = mt.form();
if (form.primsAtEnd == form.erasedType)
// quick check shows no reordering is necessary
return null;
int argc = form.parameterCount();
int[] paramOrder = new int[argc];
// 3-way bucket sort:
int pac = form.primitiveParameterCount();
int lac = form.longPrimitiveParameterCount();
int rfill = 0, ifill = argc - pac, lfill = argc - lac;
Class<?>[] ptypes = mt.ptypes();
boolean changed = false;
for (int i = 0; i < ptypes.length; i++) {
Class<?> pt = ptypes[i];
int ord;
if (!pt.isPrimitive()) ord = rfill++;
else if (!hasTwoArgSlots(pt)) ord = ifill++;
else ord = lfill++;
if (ord != i) changed = true;
assert(paramOrder[ord] == 0);
paramOrder[ord] = i;
}
assert(rfill == argc - pac && ifill == argc - lac && lfill == argc);
if (!changed) {
form.primsAtEnd = form.erasedType;
return null;
}
return paramOrder;
}
/** Put the existing parameters of mt into a new order, given by newParamOrder.
* The third argument is logically appended to mt.parameterArray,
* so that elements of newParamOrder can index either pre-existing or
* new parameter types.
*/
public static MethodType reorderParameters(MethodType mt, int[] newParamOrder, Class<?>[] moreParams) {
if (newParamOrder == null) return mt; // no-op reordering
Class<?>[] ptypes = mt.ptypes();
Class<?>[] ntypes = new Class<?>[newParamOrder.length];
int maxParam = ptypes.length + (moreParams == null ? 0 : moreParams.length);
boolean changed = (ntypes.length != ptypes.length);
for (int i = 0; i < newParamOrder.length; i++) {
int param = newParamOrder[i];
if (param != i) changed = true;
Class<?> nt;
if (param < ptypes.length) nt = ptypes[param];
else if (param == maxParam) nt = mt.returnType();
else nt = moreParams[param - ptypes.length];
ntypes[i] = nt;
}
if (!changed) return mt;
return MethodType.makeImpl(mt.returnType(), ntypes, true);
}
private static boolean hasTwoArgSlots(Class<?> type) {
return type == long.class || type == double.class;
}
private static long pack(int a, int b, int c, int d) {
assert(((a|b|c|d) & ~0xFFFF) == 0);
long hw = ((a << 16) | b), lw = ((c << 16) | d);
return (hw << 32) | lw;
}
private static char unpack(long packed, int word) { // word==0 => return a, ==3 => return d
assert(word <= 3);
return (char)(packed >> ((3-word) * 16));
}
public int parameterCount() { // # outgoing values
return unpack(argCounts, 3);
}
public int parameterSlotCount() { // # outgoing interpreter slots
return unpack(argCounts, 2);
}
public int returnCount() { // = 0 (V), or 1
return unpack(argCounts, 1);
}
public int returnSlotCount() { // = 0 (V), 2 (J/D), or 1
return unpack(argCounts, 0);
}
public int primitiveParameterCount() {
return unpack(primCounts, 3);
}
public int longPrimitiveParameterCount() {
return unpack(primCounts, 2);
}
public int primitiveReturnCount() { // = 0 (obj), or 1
return unpack(primCounts, 1);
}
public int longPrimitiveReturnCount() { // = 1 (J/D), or 0
return unpack(primCounts, 0);
}
public boolean hasPrimitives() {
return primCounts != 0;
}
// public boolean hasNonVoidPrimitives() {
// if (primCounts == 0) return false;
// if (primitiveParameterCount() != 0) return true;
// return (primitiveReturnCount() != 0 && returnCount() != 0);
// }
public boolean hasLongPrimitives() {
return (longPrimitiveParameterCount() | longPrimitiveReturnCount()) != 0;
}
public int parameterToArgSlot(int i) {
return argToSlotTable[1+i];
}
public int argSlotToParameter(int argSlot) {
// Note: Empty slots are represented by zero in this table.
// Valid arguments slots contain incremented entries, so as to be non-zero.
// We return -1 the caller to mean an empty slot.
return slotToArgTable[argSlot] - 1;
}
static MethodTypeForm findForm(MethodType mt) {
MethodType erased = canonicalize(mt, ERASE, ERASE);
if (erased == null) {
// It is already erased. Make a new MethodTypeForm.
return new MethodTypeForm(mt);
} else {
// Share the MethodTypeForm with the erased version.
return erased.form();
}
}
/** Codes for {@link #canonicalize(java.lang.Class, int)}.
* ERASE means change every reference to {@code Object}.
* WRAP means convert primitives (including {@code void} to their
* corresponding wrapper types. UNWRAP means the reverse of WRAP.
* INTS means convert all non-void primitive types to int or long,
* according to size. LONGS means convert all non-void primitives
* to long, regardless of size. RAW_RETURN means convert a type
* (assumed to be a return type) to int if it is smaller than an int,
* or if it is void.
*/
public static final int NO_CHANGE = 0, ERASE = 1, WRAP = 2, UNWRAP = 3, INTS = 4, LONGS = 5, RAW_RETURN = 6;
/** Canonicalize the types in the given method type.
* If any types change, intern the new type, and return it.
* Otherwise return null.
*/
public static MethodType canonicalize(MethodType mt, int howRet, int howArgs) {
Class<?>[] ptypes = mt.ptypes();
Class<?>[] ptc = MethodTypeForm.canonicalizes(ptypes, howArgs);
Class<?> rtype = mt.returnType();
Class<?> rtc = MethodTypeForm.canonicalize(rtype, howRet);
if (ptc == null && rtc == null) {
// It is already canonical.
return null;
}
// Find the erased version of the method type:
if (rtc == null) rtc = rtype;
if (ptc == null) ptc = ptypes;
return MethodType.makeImpl(rtc, ptc, true);
}
/** Canonicalize the given return or param type.
* Return null if the type is already canonicalized.
*/
static Class<?> canonicalize(Class<?> t, int how) {
Class<?> ct;
if (t == Object.class) {
// no change, ever
} else if (!t.isPrimitive()) {
switch (how) {
case UNWRAP:
ct = Wrapper.asPrimitiveType(t);
if (ct != t) return ct;
break;
case RAW_RETURN:
case ERASE:
return Object.class;
}
} else if (t == void.class) {
// no change, usually
switch (how) {
case RAW_RETURN:
return int.class;
case WRAP:
return Void.class;
}
} else {
// non-void primitive
switch (how) {
case WRAP:
return Wrapper.asWrapperType(t);
case INTS:
if (t == int.class || t == long.class)
return null; // no change
if (t == double.class)
return long.class;
return int.class;
case LONGS:
if (t == long.class)
return null; // no change
return long.class;
case RAW_RETURN:
if (t == int.class || t == long.class ||
t == float.class || t == double.class)
return null; // no change
// everything else returns as an int
return int.class;
}
}
// no change; return null to signify
return null;
}
/** Canonicalize each param type in the given array.
* Return null if all types are already canonicalized.
*/
static Class<?>[] canonicalizes(Class<?>[] ts, int how) {
Class<?>[] cs = null;
for (int imax = ts.length, i = 0; i < imax; i++) {
Class<?> c = canonicalize(ts[i], how);
if (c == void.class)
c = null; // a Void parameter was unwrapped to void; ignore
if (c != null) {
if (cs == null)
cs = ts.clone();
cs[i] = c;
}
}
return cs;
}
/*non-public*/ void notifyGenericMethodType() {
if (genericInvoker != null) return;
try {
// Trigger adapter creation.
genericInvoker = InvokeGeneric.generalInvokerOf(erasedType);
} catch (Exception ex) {
Error err = new InternalError("Exception while resolving inexact invoke");
err.initCause(ex);
throw err;
}
}
@Override
public String toString() {
return "Form"+erasedType;
}
}