--- /dev/null 2009-02-04 23:35:29.000000000 -0800 +++ new/src/share/classes/java/dyn/MethodTypeForm.java 2009-02-04 23:35:29.000000000 -0800 @@ -0,0 +1,249 @@ +/* + * Copyright 2008-2009 Sun Microsystems, Inc. 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. Sun designates this + * particular file as subject to the "Classpath" exception as provided + * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + */ + +package java.dyn; + +import impl.java.dyn.util.Wrappers; + +/** + * Shared information for a group of method types, which differ + * only by reference types, and therefore share a common erasure + * and wrapping. + *

+ * For an empirical discussion of the structure of method types, + * see + * the thread "Avoiding Boxing" on jvm-languages. + * 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 + final MethodType erasedType; // the canonical erasure + final MethodType wrappedType; // erasure, with primitives wrapped + + public static MethodTypeForm of(MethodType type) { + return type.form; + } + + private MethodTypeForm(MethodType erase) { + this.erasedType = erase; + MethodType wt = canonType(erase, WRAP); + this.wrappedType = (wt == null) ? erase : wt; + + int ptypeCount = erase.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. + if (wt != null) { + int pac = 0, lac = 0, prc = 0, lrc = 0; + Class epts[] = erase.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 = erase.rtype; + 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); + } else { + this.primCounts = 0; + } + 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 new IllegalArgumentException("too many arguments"); + + // send a few bits down to the JVM: + this.vmslots = parameterSlotCount(); + } + + 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 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 final int ERASE = 1, WRAP = 2, UNWRAP = 4, ARGS_ONLY = 8; + + static MethodTypeForm findForm(MethodType mt) { + MethodType erased = canonType(mt, 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; + } + } + + /** Canonicalize the types in the given method type. + * If any types change, intern the new type, and return it. + * Otherwise return null. + */ + static MethodType canonType(MethodType mt, int how) { + Class[] ptc = MethodTypeForm.canonTypes(mt.ptypes, how); + Class rtc = null; + if ((how & ARGS_ONLY) == 0) + rtc = MethodTypeForm.canonType(mt.rtype, how); + if (ptc == null && rtc == null) { + // It is already canonical. + return null; + } + // Find the erased version of the method type: + if (rtc == null) rtc = mt.rtype; + if (ptc == null) ptc = mt.ptypes; + return MethodType.makeImpl(rtc, ptc, true); + } + + /** Canonicalize the given return or param type. + * Return null if the type is already canonicalized. + */ + static Class canonType(Class t, int how) { + if (t == Object.class) { + // no change, ever + } else if (!t.isPrimitive()) { + if ((how & UNWRAP) != 0) { + Class pt = Wrappers.asPrimitiveType(t); + if (pt != t) + return pt; + } + if ((how & ERASE) != 0) + return Object.class; + } else { + if ((how & WRAP) != 0) { + if ((how & ERASE) != 0) + return Object.class; + return Wrappers.asWrapperType(t); + } + } + // 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[] canonTypes(Class[] ts, int how) { + Class[] cs = null; + for (int imax = ts.length, i = 0; i < imax; i++) { + Class c = canonType(ts[i], how); + if (c != null) { + if (cs == null) + cs = ts.clone(); + cs[i] = c; + } + } + return cs; + } +}