1 /* 2 * Copyright (c) 2008, 2013, 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 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP; 32 33 /** 34 * Shared information for a group of method types, which differ 35 * only by reference types, and therefore share a common erasure 36 * and wrapping. 37 * <p> 38 * For an empirical discussion of the structure of method types, 39 * see <a href="http://groups.google.com/group/jvm-languages/browse_thread/thread/ac9308ae74da9b7e/"> 40 * the thread "Avoiding Boxing" on jvm-languages</a>. 41 * There are approximately 2000 distinct erased method types in the JDK. 42 * There are a little over 10 times that number of unerased types. 43 * No more than half of these are likely to be loaded at once. 44 * @author John Rose 45 */ 46 final class MethodTypeForm { 47 final int[] argToSlotTable, slotToArgTable; 48 final long argCounts; // packed slot & value counts 49 final long primCounts; // packed prim & double counts 50 final int vmslots; // total number of parameter slots 51 final MethodType erasedType; // the canonical erasure 52 final MethodType basicType; // the canonical erasure, with primitives simplified 53 54 // Cached adapter information: 55 @Stable String typeString; // argument type signature characters 56 @Stable MethodHandle genericInvoker; // JVM hook for inexact invoke 57 @Stable MethodHandle basicInvoker; // cached instance of MH.invokeBasic 58 @Stable MethodHandle namedFunctionInvoker; // cached helper for LF.NamedFunction 59 60 // Cached lambda form information, for basic types only: 61 final @Stable LambdaForm[] lambdaForms; 62 // Indexes into lambdaForms: 63 static final int 64 LF_INVVIRTUAL = 0, // DMH invokeVirtual 65 LF_INVSTATIC = 1, 66 LF_INVSPECIAL = 2, 67 LF_NEWINVSPECIAL = 3, 68 LF_INVINTERFACE = 4, 69 LF_INVSTATIC_INIT = 5, // DMH invokeStatic with <clinit> barrier 70 LF_INTERPRET = 6, // LF interpreter 71 LF_COUNTER = 7, // CMH wrapper 72 LF_REINVOKE = 8, // other wrapper 73 LF_EX_LINKER = 9, // invokeExact_MT 74 LF_EX_INVOKER = 10, // invokeExact MH 75 LF_GEN_LINKER = 11, 76 LF_GEN_INVOKER = 12, 77 LF_CS_LINKER = 13, // linkToCallSite_CS 78 LF_MH_LINKER = 14, // linkToCallSite_MH 79 LF_LIMIT = 15; 80 81 public MethodType erasedType() { 82 return erasedType; 83 } 84 85 public MethodType basicType() { 86 return basicType; 87 } 88 89 public LambdaForm cachedLambdaForm(int which) { 90 return lambdaForms[which]; 91 } 92 93 public LambdaForm setCachedLambdaForm(int which, LambdaForm form) { 94 // Should we perform some sort of CAS, to avoid racy duplication? 95 return lambdaForms[which] = form; 96 } 97 98 public MethodHandle basicInvoker() { 99 assert(erasedType == basicType) : "erasedType: " + erasedType + " != basicType: " + basicType; // primitives must be flattened also 100 MethodHandle invoker = basicInvoker; 101 if (invoker != null) return invoker; 102 invoker = DirectMethodHandle.make(invokeBasicMethod(basicType)); 103 basicInvoker = invoker; 104 return invoker; 105 } 106 107 // This next one is called from LambdaForm.NamedFunction.<init>. 108 /*non-public*/ static MemberName invokeBasicMethod(MethodType basicType) { 109 assert(basicType == basicType.basicType()); 110 try { 111 // Do approximately the same as this public API call: 112 // Lookup.findVirtual(MethodHandle.class, name, type); 113 // But bypass access and corner case checks, since we know exactly what we need. 114 return IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, MethodHandle.class, "invokeBasic", basicType); 115 } catch (ReflectiveOperationException ex) { 116 throw newInternalError("JVM cannot find invoker for "+basicType, ex); 117 } 118 } 119 120 /** 121 * Build an MTF for a given type, which must have all references erased to Object. 122 * This MTF will stand for that type and all un-erased variations. 123 * Eagerly compute some basic properties of the type, common to all variations. 124 */ 125 protected MethodTypeForm(MethodType erasedType) { 126 this.erasedType = erasedType; 127 128 Class<?>[] ptypes = erasedType.ptypes(); 129 int ptypeCount = ptypes.length; 130 int pslotCount = ptypeCount; // temp. estimate 131 int rtypeCount = 1; // temp. estimate 132 int rslotCount = 1; // temp. estimate 133 134 int[] argToSlotTab = null, slotToArgTab = null; 135 136 // Walk the argument types, looking for primitives. 137 int pac = 0, lac = 0, prc = 0, lrc = 0; 138 Class<?>[] epts = ptypes; 139 Class<?>[] bpts = epts; 140 for (int i = 0; i < epts.length; i++) { 141 Class<?> pt = epts[i]; 142 if (pt != Object.class) { 143 ++pac; 144 Wrapper w = Wrapper.forPrimitiveType(pt); 145 if (w.isDoubleWord()) ++lac; 146 if (w.isSubwordOrInt() && pt != int.class) { 147 if (bpts == epts) 148 bpts = bpts.clone(); 149 bpts[i] = int.class; 150 } 151 } 152 } 153 pslotCount += lac; // #slots = #args + #longs 154 Class<?> rt = erasedType.returnType(); 155 Class<?> bt = rt; 156 if (rt != Object.class) { 157 ++prc; // even void.class counts as a prim here 158 Wrapper w = Wrapper.forPrimitiveType(rt); 159 if (w.isDoubleWord()) ++lrc; 160 if (w.isSubwordOrInt() && rt != int.class) 161 bt = int.class; 162 // adjust #slots, #args 163 if (rt == void.class) 164 rtypeCount = rslotCount = 0; 165 else 166 rslotCount += lrc; 167 } 168 if (epts == bpts && bt == rt) { 169 this.basicType = erasedType; 170 } else { 171 this.basicType = MethodType.makeImpl(bt, bpts, true); 172 } 173 if (lac != 0) { 174 int slot = ptypeCount + lac; 175 slotToArgTab = new int[slot+1]; 176 argToSlotTab = new int[1+ptypeCount]; 177 argToSlotTab[0] = slot; // argument "-1" is past end of slots 178 for (int i = 0; i < epts.length; i++) { 179 Class<?> pt = epts[i]; 180 Wrapper w = Wrapper.forBasicType(pt); 181 if (w.isDoubleWord()) --slot; 182 --slot; 183 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 184 argToSlotTab[1+i] = slot; 185 } 186 assert(slot == 0); // filled the table 187 } 188 this.primCounts = pack(lrc, prc, lac, pac); 189 this.argCounts = pack(rslotCount, rtypeCount, pslotCount, ptypeCount); 190 if (slotToArgTab == null) { 191 int slot = ptypeCount; // first arg is deepest in stack 192 slotToArgTab = new int[slot+1]; 193 argToSlotTab = new int[1+ptypeCount]; 194 argToSlotTab[0] = slot; // argument "-1" is past end of slots 195 for (int i = 0; i < ptypeCount; i++) { 196 --slot; 197 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 198 argToSlotTab[1+i] = slot; 199 } 200 } 201 this.argToSlotTable = argToSlotTab; 202 this.slotToArgTable = slotToArgTab; 203 204 if (pslotCount >= 256) throw newIllegalArgumentException("too many arguments"); 205 206 // send a few bits down to the JVM: 207 this.vmslots = parameterSlotCount(); 208 209 if (basicType == erasedType) { 210 lambdaForms = new LambdaForm[LF_LIMIT]; 211 } else { 212 lambdaForms = null; // could be basicType.form().lambdaForms; 213 } 214 } 215 216 private static long pack(int a, int b, int c, int d) { 217 assert(((a|b|c|d) & ~0xFFFF) == 0); 218 long hw = ((a << 16) | b), lw = ((c << 16) | d); 219 return (hw << 32) | lw; 220 } 221 private static char unpack(long packed, int word) { // word==0 => return a, ==3 => return d 222 assert(word <= 3); 223 return (char)(packed >> ((3-word) * 16)); 224 } 225 226 public int parameterCount() { // # outgoing values 227 return unpack(argCounts, 3); 228 } 229 public int parameterSlotCount() { // # outgoing interpreter slots 230 return unpack(argCounts, 2); 231 } 232 public int returnCount() { // = 0 (V), or 1 233 return unpack(argCounts, 1); 234 } 235 public int returnSlotCount() { // = 0 (V), 2 (J/D), or 1 236 return unpack(argCounts, 0); 237 } 238 public int primitiveParameterCount() { 239 return unpack(primCounts, 3); 240 } 241 public int longPrimitiveParameterCount() { 242 return unpack(primCounts, 2); 243 } 244 public int primitiveReturnCount() { // = 0 (obj), or 1 245 return unpack(primCounts, 1); 246 } 247 public int longPrimitiveReturnCount() { // = 1 (J/D), or 0 248 return unpack(primCounts, 0); 249 } 250 public boolean hasPrimitives() { 251 return primCounts != 0; 252 } 253 public boolean hasNonVoidPrimitives() { 254 if (primCounts == 0) return false; 255 if (primitiveParameterCount() != 0) return true; 256 return (primitiveReturnCount() != 0 && returnCount() != 0); 257 } 258 public boolean hasLongPrimitives() { 259 return (longPrimitiveParameterCount() | longPrimitiveReturnCount()) != 0; 260 } 261 public int parameterToArgSlot(int i) { 262 return argToSlotTable[1+i]; 263 } 264 public int argSlotToParameter(int argSlot) { 265 // Note: Empty slots are represented by zero in this table. 266 // Valid arguments slots contain incremented entries, so as to be non-zero. 267 // We return -1 the caller to mean an empty slot. 268 return slotToArgTable[argSlot] - 1; 269 } 270 271 static MethodTypeForm findForm(MethodType mt) { 272 MethodType erased = canonicalize(mt, ERASE, ERASE); 273 if (erased == null) { 274 // It is already erased. Make a new MethodTypeForm. 275 return new MethodTypeForm(mt); 276 } else { 277 // Share the MethodTypeForm with the erased version. 278 return erased.form(); 279 } 280 } 281 282 /** Codes for {@link #canonicalize(java.lang.Class, int)}. 283 * ERASE means change every reference to {@code Object}. 284 * WRAP means convert primitives (including {@code void} to their 285 * corresponding wrapper types. UNWRAP means the reverse of WRAP. 286 * INTS means convert all non-void primitive types to int or long, 287 * according to size. LONGS means convert all non-void primitives 288 * to long, regardless of size. RAW_RETURN means convert a type 289 * (assumed to be a return type) to int if it is smaller than an int, 290 * or if it is void. 291 */ 292 public static final int NO_CHANGE = 0, ERASE = 1, WRAP = 2, UNWRAP = 3, INTS = 4, LONGS = 5, RAW_RETURN = 6; 293 294 /** Canonicalize the types in the given method type. 295 * If any types change, intern the new type, and return it. 296 * Otherwise return null. 297 */ 298 public static MethodType canonicalize(MethodType mt, int howRet, int howArgs) { 299 Class<?>[] ptypes = mt.ptypes(); 300 Class<?>[] ptc = MethodTypeForm.canonicalizes(ptypes, howArgs); 301 Class<?> rtype = mt.returnType(); 302 Class<?> rtc = MethodTypeForm.canonicalize(rtype, howRet); 303 if (ptc == null && rtc == null) { 304 // It is already canonical. 305 return null; 306 } 307 // Find the erased version of the method type: 308 if (rtc == null) rtc = rtype; 309 if (ptc == null) ptc = ptypes; 310 return MethodType.makeImpl(rtc, ptc, true); 311 } 312 313 /** Canonicalize the given return or param type. 314 * Return null if the type is already canonicalized. 315 */ 316 static Class<?> canonicalize(Class<?> t, int how) { 317 Class<?> ct; 318 if (t == Object.class) { 319 // no change, ever 320 } else if (!t.isPrimitive()) { 321 switch (how) { 322 case UNWRAP: 323 ct = Wrapper.asPrimitiveType(t); 324 if (ct != t) return ct; 325 break; 326 case RAW_RETURN: 327 case ERASE: 328 return Object.class; 329 } 330 } else if (t == void.class) { 331 // no change, usually 332 switch (how) { 333 case RAW_RETURN: 334 return int.class; 335 case WRAP: 336 return Void.class; 337 } 338 } else { 339 // non-void primitive 340 switch (how) { 341 case WRAP: 342 return Wrapper.asWrapperType(t); 343 case INTS: 344 if (t == int.class || t == long.class) 345 return null; // no change 346 if (t == double.class) 347 return long.class; 348 return int.class; 349 case LONGS: 350 if (t == long.class) 351 return null; // no change 352 return long.class; 353 case RAW_RETURN: 354 if (t == int.class || t == long.class || 355 t == float.class || t == double.class) 356 return null; // no change 357 // everything else returns as an int 358 return int.class; 359 } 360 } 361 // no change; return null to signify 362 return null; 363 } 364 365 /** Canonicalize each param type in the given array. 366 * Return null if all types are already canonicalized. 367 */ 368 static Class<?>[] canonicalizes(Class<?>[] ts, int how) { 369 Class<?>[] cs = null; 370 for (int imax = ts.length, i = 0; i < imax; i++) { 371 Class<?> c = canonicalize(ts[i], how); 372 if (c == void.class) 373 c = null; // a Void parameter was unwrapped to void; ignore 374 if (c != null) { 375 if (cs == null) 376 cs = ts.clone(); 377 cs[i] = c; 378 } 379 } 380 return cs; 381 } 382 383 @Override 384 public String toString() { 385 return "Form"+erasedType; 386 } 387 388 }