1 /* 2 * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.invoke; 27 28 import sun.invoke.util.Wrapper; 29 import static java.lang.invoke.MethodHandleStatics.*; 30 import static java.lang.invoke.MethodHandleNatives.Constants.*; 31 32 /** 33 * Shared information for a group of method types, which differ 34 * only by reference types, and therefore share a common erasure 35 * and wrapping. 36 * <p> 37 * For an empirical discussion of the structure of method types, 38 * see <a href="http://groups.google.com/group/jvm-languages/browse_thread/thread/ac9308ae74da9b7e/"> 39 * the thread "Avoiding Boxing" on jvm-languages</a>. 40 * There are approximately 2000 distinct erased method types in the JDK. 41 * There are a little over 10 times that number of unerased types. 42 * No more than half of these are likely to be loaded at once. 43 * @author John Rose 44 */ 45 final class MethodTypeForm { 46 final int[] argToSlotTable, slotToArgTable; 47 final long argCounts; // packed slot & value counts 48 final long primCounts; // packed prim & double counts 49 final int vmslots; // total number of parameter slots 50 final MethodType erasedType; // the canonical erasure 51 final MethodType basicType; // the canonical erasure, with primitives simplified 52 53 // Cached adapter information: 54 /*lazy*/ MethodHandle genericInvoker; // JVM hook for inexact invoke 55 /*lazy*/ MethodHandle basicInvoker; // cached instance of MH.invokeBasic 56 /*lazy*/ MethodHandle namedFunctionInvoker; // cached helper for LF.NamedFunction 57 58 // Cached lambda form information, for basic types only: 59 final LambdaForm[] lambdaForms; 60 // Indexes into lambdaForms: 61 static final int 62 LF_INVVIRTUAL = 0, // DMH invokeVirtual 63 LF_INVSTATIC = 1, 64 LF_INVSPECIAL = 2, 65 LF_NEWINVSPECIAL = 3, 66 LF_INVINTERFACE = 4, 67 LF_INVSTATIC_INIT = 5, // DMH invokeStatic with <clinit> barrier 68 LF_INTERPRET = 6, // LF interpreter 69 LF_COUNTER = 7, // CMH wrapper 70 LF_REINVOKE = 8, // other wrapper 71 LF_EX_LINKER = 9, // invokeExact_MT 72 LF_EX_INVOKER = 10, // invokeExact MH 73 LF_GEN_LINKER = 11, 74 LF_GEN_INVOKER = 12, 75 LF_CS_LINKER = 13, // linkToCallSite_CS 76 LF_LIMIT = 14; 77 78 public MethodType erasedType() { 79 return erasedType; 80 } 81 82 public MethodType basicType() { 83 return basicType; 84 } 85 86 public LambdaForm cachedLambdaForm(int which) { 87 return lambdaForms[which]; 88 } 89 90 public LambdaForm setCachedLambdaForm(int which, LambdaForm form) { 91 // Should we perform some sort of CAS, to avoid racy duplication? 92 return lambdaForms[which] = form; 93 } 94 95 public MethodHandle basicInvoker() { 96 assert(erasedType == basicType) : "erasedType: " + erasedType + " != basicType: " + basicType; // primitives must be flattened also 97 MethodHandle invoker = basicInvoker; 98 if (invoker != null) return invoker; 99 invoker = basicType.invokers().makeBasicInvoker(); 100 basicInvoker = invoker; 101 return invoker; 102 } 103 104 /** 105 * Build an MTF for a given type, which must have all references erased to Object. 106 * This MTF will stand for that type and all un-erased variations. 107 * Eagerly compute some basic properties of the type, common to all variations. 108 */ 109 protected MethodTypeForm(MethodType erasedType) { 110 this.erasedType = erasedType; 111 112 Class<?>[] ptypes = erasedType.ptypes(); 113 int ptypeCount = ptypes.length; 114 int pslotCount = ptypeCount; // temp. estimate 115 int rtypeCount = 1; // temp. estimate 116 int rslotCount = 1; // temp. estimate 117 118 int[] argToSlotTab = null, slotToArgTab = null; 119 120 // Walk the argument types, looking for primitives. 121 int pac = 0, lac = 0, prc = 0, lrc = 0; 122 Class<?>[] epts = ptypes; 123 Class<?>[] bpts = epts; 124 for (int i = 0; i < epts.length; i++) { 125 Class<?> pt = epts[i]; 126 if (pt != Object.class) { 127 ++pac; 128 Wrapper w = Wrapper.forPrimitiveType(pt); 129 if (w.isDoubleWord()) ++lac; 130 if (w.isSubwordOrInt() && pt != int.class) { 131 if (bpts == epts) 132 bpts = bpts.clone(); 133 bpts[i] = int.class; 134 } 135 } 136 } 137 pslotCount += lac; // #slots = #args + #longs 138 Class<?> rt = erasedType.returnType(); 139 Class<?> bt = rt; 140 if (rt != Object.class) { 141 ++prc; // even void.class counts as a prim here 142 Wrapper w = Wrapper.forPrimitiveType(rt); 143 if (w.isDoubleWord()) ++lrc; 144 if (w.isSubwordOrInt() && rt != int.class) 145 bt = int.class; 146 // adjust #slots, #args 147 if (rt == void.class) 148 rtypeCount = rslotCount = 0; 149 else 150 rslotCount += lrc; 151 } 152 if (epts == bpts && bt == rt) { 153 this.basicType = erasedType; 154 } else { 155 this.basicType = MethodType.makeImpl(bt, bpts, true); 156 } 157 if (lac != 0) { 158 int slot = ptypeCount + lac; 159 slotToArgTab = new int[slot+1]; 160 argToSlotTab = new int[1+ptypeCount]; 161 argToSlotTab[0] = slot; // argument "-1" is past end of slots 162 for (int i = 0; i < epts.length; i++) { 163 Class<?> pt = epts[i]; 164 Wrapper w = Wrapper.forBasicType(pt); 165 if (w.isDoubleWord()) --slot; 166 --slot; 167 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 168 argToSlotTab[1+i] = slot; 169 } 170 assert(slot == 0); // filled the table 171 } 172 this.primCounts = pack(lrc, prc, lac, pac); 173 this.argCounts = pack(rslotCount, rtypeCount, pslotCount, ptypeCount); 174 if (slotToArgTab == null) { 175 int slot = ptypeCount; // first arg is deepest in stack 176 slotToArgTab = new int[slot+1]; 177 argToSlotTab = new int[1+ptypeCount]; 178 argToSlotTab[0] = slot; // argument "-1" is past end of slots 179 for (int i = 0; i < ptypeCount; i++) { 180 --slot; 181 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 182 argToSlotTab[1+i] = slot; 183 } 184 } 185 this.argToSlotTable = argToSlotTab; 186 this.slotToArgTable = slotToArgTab; 187 188 if (pslotCount >= 256) throw newIllegalArgumentException("too many arguments"); 189 190 // send a few bits down to the JVM: 191 this.vmslots = parameterSlotCount(); 192 193 if (basicType == erasedType) { 194 lambdaForms = new LambdaForm[LF_LIMIT]; 195 } else { 196 lambdaForms = null; // could be basicType.form().lambdaForms; 197 } 198 } 199 200 private static long pack(int a, int b, int c, int d) { 201 assert(((a|b|c|d) & ~0xFFFF) == 0); 202 long hw = ((a << 16) | b), lw = ((c << 16) | d); 203 return (hw << 32) | lw; 204 } 205 private static char unpack(long packed, int word) { // word==0 => return a, ==3 => return d 206 assert(word <= 3); 207 return (char)(packed >> ((3-word) * 16)); 208 } 209 210 public int parameterCount() { // # outgoing values 211 return unpack(argCounts, 3); 212 } 213 public int parameterSlotCount() { // # outgoing interpreter slots 214 return unpack(argCounts, 2); 215 } 216 public int returnCount() { // = 0 (V), or 1 217 return unpack(argCounts, 1); 218 } 219 public int returnSlotCount() { // = 0 (V), 2 (J/D), or 1 220 return unpack(argCounts, 0); 221 } 222 public int primitiveParameterCount() { 223 return unpack(primCounts, 3); 224 } 225 public int longPrimitiveParameterCount() { 226 return unpack(primCounts, 2); 227 } 228 public int primitiveReturnCount() { // = 0 (obj), or 1 229 return unpack(primCounts, 1); 230 } 231 public int longPrimitiveReturnCount() { // = 1 (J/D), or 0 232 return unpack(primCounts, 0); 233 } 234 public boolean hasPrimitives() { 235 return primCounts != 0; 236 } 237 public boolean hasNonVoidPrimitives() { 238 if (primCounts == 0) return false; 239 if (primitiveParameterCount() != 0) return true; 240 return (primitiveReturnCount() != 0 && returnCount() != 0); 241 } 242 public boolean hasLongPrimitives() { 243 return (longPrimitiveParameterCount() | longPrimitiveReturnCount()) != 0; 244 } 245 public int parameterToArgSlot(int i) { 246 return argToSlotTable[1+i]; 247 } 248 public int argSlotToParameter(int argSlot) { 249 // Note: Empty slots are represented by zero in this table. 250 // Valid arguments slots contain incremented entries, so as to be non-zero. 251 // We return -1 the caller to mean an empty slot. 252 return slotToArgTable[argSlot] - 1; 253 } 254 255 static MethodTypeForm findForm(MethodType mt) { 256 MethodType erased = canonicalize(mt, ERASE, ERASE); 257 if (erased == null) { 258 // It is already erased. Make a new MethodTypeForm. 259 return new MethodTypeForm(mt); 260 } else { 261 // Share the MethodTypeForm with the erased version. 262 return erased.form(); 263 } 264 } 265 266 /** Codes for {@link #canonicalize(java.lang.Class, int)}. 267 * ERASE means change every reference to {@code Object}. 268 * WRAP means convert primitives (including {@code void} to their 269 * corresponding wrapper types. UNWRAP means the reverse of WRAP. 270 * INTS means convert all non-void primitive types to int or long, 271 * according to size. LONGS means convert all non-void primitives 272 * to long, regardless of size. RAW_RETURN means convert a type 273 * (assumed to be a return type) to int if it is smaller than an int, 274 * or if it is void. 275 */ 276 public static final int NO_CHANGE = 0, ERASE = 1, WRAP = 2, UNWRAP = 3, INTS = 4, LONGS = 5, RAW_RETURN = 6; 277 278 /** Canonicalize the types in the given method type. 279 * If any types change, intern the new type, and return it. 280 * Otherwise return null. 281 */ 282 public static MethodType canonicalize(MethodType mt, int howRet, int howArgs) { 283 Class<?>[] ptypes = mt.ptypes(); 284 Class<?>[] ptc = MethodTypeForm.canonicalizes(ptypes, howArgs); 285 Class<?> rtype = mt.returnType(); 286 Class<?> rtc = MethodTypeForm.canonicalize(rtype, howRet); 287 if (ptc == null && rtc == null) { 288 // It is already canonical. 289 return null; 290 } 291 // Find the erased version of the method type: 292 if (rtc == null) rtc = rtype; 293 if (ptc == null) ptc = ptypes; 294 return MethodType.makeImpl(rtc, ptc, true); 295 } 296 297 /** Canonicalize the given return or param type. 298 * Return null if the type is already canonicalized. 299 */ 300 static Class<?> canonicalize(Class<?> t, int how) { 301 Class<?> ct; 302 if (t == Object.class) { 303 // no change, ever 304 } else if (!t.isPrimitive()) { 305 switch (how) { 306 case UNWRAP: 307 ct = Wrapper.asPrimitiveType(t); 308 if (ct != t) return ct; 309 break; 310 case RAW_RETURN: 311 case ERASE: 312 return Object.class; 313 } 314 } else if (t == void.class) { 315 // no change, usually 316 switch (how) { 317 case RAW_RETURN: 318 return int.class; 319 case WRAP: 320 return Void.class; 321 } 322 } else { 323 // non-void primitive 324 switch (how) { 325 case WRAP: 326 return Wrapper.asWrapperType(t); 327 case INTS: 328 if (t == int.class || t == long.class) 329 return null; // no change 330 if (t == double.class) 331 return long.class; 332 return int.class; 333 case LONGS: 334 if (t == long.class) 335 return null; // no change 336 return long.class; 337 case RAW_RETURN: 338 if (t == int.class || t == long.class || 339 t == float.class || t == double.class) 340 return null; // no change 341 // everything else returns as an int 342 return int.class; 343 } 344 } 345 // no change; return null to signify 346 return null; 347 } 348 349 /** Canonicalize each param type in the given array. 350 * Return null if all types are already canonicalized. 351 */ 352 static Class<?>[] canonicalizes(Class<?>[] ts, int how) { 353 Class<?>[] cs = null; 354 for (int imax = ts.length, i = 0; i < imax; i++) { 355 Class<?> c = canonicalize(ts[i], how); 356 if (c == void.class) 357 c = null; // a Void parameter was unwrapped to void; ignore 358 if (c != null) { 359 if (cs == null) 360 cs = ts.clone(); 361 cs[i] = c; 362 } 363 } 364 return cs; 365 } 366 367 @Override 368 public String toString() { 369 return "Form"+erasedType; 370 } 371 372 }