/* * Copyright (c) 2008, 2013, 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.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 * 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 */ final class MethodTypeForm { final int[] argToSlotTable, slotToArgTable; final long argCounts; // packed slot & value counts final long primCounts; // packed prim & double counts final MethodType erasedType; // the canonical erasure final MethodType basicType; // the canonical erasure, with primitives simplified // Cached adapter information: @Stable MethodHandle namedFunctionInvoker; // cached helper for LF.NamedFunction // Cached lambda form information, for basic types only: final @Stable LambdaForm[] lambdaForms; // Indexes into lambdaForms: static final int LF_INVVIRTUAL = 0, // DMH invokeVirtual LF_INVSTATIC = 1, LF_INVSPECIAL = 2, LF_NEWINVSPECIAL = 3, LF_INVINTERFACE = 4, LF_INVSTATIC_INIT = 5, // DMH invokeStatic with barrier LF_INTERPRET = 6, // LF interpreter LF_COUNTER = 7, // CMH wrapper LF_REINVOKE = 8, // other wrapper LF_EX_LINKER = 9, // invokeExact_MT (for invokehandle) LF_EX_INVOKER = 10, // MHs.invokeExact LF_GEN_LINKER = 11, // generic invoke_MT (for invokehandle) LF_GEN_INVOKER = 12, // generic MHs.invoke LF_CS_LINKER = 13, // linkToCallSite_CS LF_MH_LINKER = 14, // linkToCallSite_MH LF_GWC = 15, // guardWithCatch (catchException) LF_LIMIT = 16; /** Return the type corresponding uniquely (1-1) to this MT-form. * It might have any primitive returns or arguments, but will have no references except Object. */ public MethodType erasedType() { return erasedType; } /** Return the basic type derived from the erased type of this MT-form. * A basic type is erased (all references Object) and also has all primitive * types (except int, long, float, double, void) normalized to int. * Such basic types correspond to low-level JVM calling sequences. */ public MethodType basicType() { return basicType; } private boolean assertIsBasicType() { // primitives must be flattened also assert(erasedType == basicType) : "erasedType: " + erasedType + " != basicType: " + basicType; return true; } public LambdaForm cachedLambdaForm(int which) { assert(assertIsBasicType()); return lambdaForms[which]; } synchronized public LambdaForm setCachedLambdaForm(int which, LambdaForm form) { // Simulate a CAS, to avoid racy duplication of results. LambdaForm prev = lambdaForms[which]; if (prev != null) return prev; return lambdaForms[which] = form; } /** * 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. * Eagerly compute some basic properties of the type, common to all variations. */ 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; Class[] bpts = epts; for (int i = 0; i < epts.length; i++) { Class pt = epts[i]; if (pt != Object.class) { ++pac; Wrapper w = Wrapper.forPrimitiveType(pt); if (w.isDoubleWord()) ++lac; if (w.isSubwordOrInt() && pt != int.class) { if (bpts == epts) bpts = bpts.clone(); bpts[i] = int.class; } } } pslotCount += lac; // #slots = #args + #longs Class rt = erasedType.returnType(); Class bt = rt; if (rt != Object.class) { ++prc; // even void.class counts as a prim here Wrapper w = Wrapper.forPrimitiveType(rt); if (w.isDoubleWord()) ++lrc; if (w.isSubwordOrInt() && rt != int.class) bt = int.class; // adjust #slots, #args if (rt == void.class) rtypeCount = rslotCount = 0; else rslotCount += lrc; } if (epts == bpts && bt == rt) { this.basicType = erasedType; } else { this.basicType = MethodType.makeImpl(bt, bpts, true); // fill in rest of data from the basic type: MethodTypeForm that = this.basicType.form(); assert(this != that); this.primCounts = that.primCounts; this.argCounts = that.argCounts; this.argToSlotTable = that.argToSlotTable; this.slotToArgTable = that.slotToArgTable; this.lambdaForms = null; return; } 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]; Wrapper w = Wrapper.forBasicType(pt); if (w.isDoubleWord()) --slot; --slot; slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note argToSlotTab[1+i] = slot; } assert(slot == 0); // filled the table } else if (pac != 0) { // have primitives but no long primitives; share slot counts with generic assert(ptypeCount == pslotCount); MethodTypeForm that = MethodType.genericMethodType(ptypeCount).form(); assert(this != that); slotToArgTab = that.slotToArgTable; argToSlotTab = that.argToSlotTable; } else { 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.primCounts = pack(lrc, prc, lac, pac); this.argCounts = pack(rslotCount, rtypeCount, pslotCount, ptypeCount); this.argToSlotTable = argToSlotTab; this.slotToArgTable = slotToArgTab; if (pslotCount >= 256) throw newIllegalArgumentException("too many arguments"); // Initialize caches, but only for basic types assert(basicType == erasedType); this.lambdaForms = new LambdaForm[LF_LIMIT]; } 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.canonicalizeAll(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[] canonicalizeAll(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; } @Override public String toString() { return "Form"+erasedType; } }