MethodTypeForm.java revision 13482:a403a4a7a831
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 26package java.lang.invoke; 27 28import jdk.internal.vm.annotation.Stable; 29import sun.invoke.util.Wrapper; 30import java.lang.ref.SoftReference; 31import static java.lang.invoke.MethodHandleStatics.*; 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 */ 46final 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 MethodType erasedType; // the canonical erasure 51 final MethodType basicType; // the canonical erasure, with primitives simplified 52 53 // Cached adapter information: 54 @Stable final SoftReference<MethodHandle>[] methodHandles; 55 // Indexes into methodHandles: 56 static final int 57 MH_BASIC_INV = 0, // cached instance of MH.invokeBasic 58 MH_NF_INV = 1, // cached helper for LF.NamedFunction 59 MH_UNINIT_CS = 2, // uninitialized call site 60 MH_LIMIT = 3; 61 62 // Cached lambda form information, for basic types only: 63 final @Stable SoftReference<LambdaForm>[] lambdaForms; 64 // Indexes into lambdaForms: 65 static final int 66 LF_INVVIRTUAL = 0, // DMH invokeVirtual 67 LF_INVSTATIC = 1, 68 LF_INVSPECIAL = 2, 69 LF_NEWINVSPECIAL = 3, 70 LF_INVINTERFACE = 4, 71 LF_INVSTATIC_INIT = 5, // DMH invokeStatic with <clinit> barrier 72 LF_INTERPRET = 6, // LF interpreter 73 LF_REBIND = 7, // BoundMethodHandle 74 LF_DELEGATE = 8, // DelegatingMethodHandle 75 LF_DELEGATE_BLOCK_INLINING = 9, // Counting DelegatingMethodHandle w/ @DontInline 76 LF_EX_LINKER = 10, // invokeExact_MT (for invokehandle) 77 LF_EX_INVOKER = 11, // MHs.invokeExact 78 LF_GEN_LINKER = 12, // generic invoke_MT (for invokehandle) 79 LF_GEN_INVOKER = 13, // generic MHs.invoke 80 LF_CS_LINKER = 14, // linkToCallSite_CS 81 LF_MH_LINKER = 15, // linkToCallSite_MH 82 LF_GWC = 16, // guardWithCatch (catchException) 83 LF_GWT = 17, // guardWithTest 84 LF_LIMIT = 18; 85 86 /** Return the type corresponding uniquely (1-1) to this MT-form. 87 * It might have any primitive returns or arguments, but will have no references except Object. 88 */ 89 public MethodType erasedType() { 90 return erasedType; 91 } 92 93 /** Return the basic type derived from the erased type of this MT-form. 94 * A basic type is erased (all references Object) and also has all primitive 95 * types (except int, long, float, double, void) normalized to int. 96 * Such basic types correspond to low-level JVM calling sequences. 97 */ 98 public MethodType basicType() { 99 return basicType; 100 } 101 102 private boolean assertIsBasicType() { 103 // primitives must be flattened also 104 assert(erasedType == basicType) 105 : "erasedType: " + erasedType + " != basicType: " + basicType; 106 return true; 107 } 108 109 public MethodHandle cachedMethodHandle(int which) { 110 assert(assertIsBasicType()); 111 SoftReference<MethodHandle> entry = methodHandles[which]; 112 return (entry != null) ? entry.get() : null; 113 } 114 115 public synchronized MethodHandle setCachedMethodHandle(int which, MethodHandle mh) { 116 // Simulate a CAS, to avoid racy duplication of results. 117 SoftReference<MethodHandle> entry = methodHandles[which]; 118 if (entry != null) { 119 MethodHandle prev = entry.get(); 120 if (prev != null) { 121 return prev; 122 } 123 } 124 methodHandles[which] = new SoftReference<>(mh); 125 return mh; 126 } 127 128 public LambdaForm cachedLambdaForm(int which) { 129 assert(assertIsBasicType()); 130 SoftReference<LambdaForm> entry = lambdaForms[which]; 131 return (entry != null) ? entry.get() : null; 132 } 133 134 public synchronized LambdaForm setCachedLambdaForm(int which, LambdaForm form) { 135 // Simulate a CAS, to avoid racy duplication of results. 136 SoftReference<LambdaForm> entry = lambdaForms[which]; 137 if (entry != null) { 138 LambdaForm prev = entry.get(); 139 if (prev != null) { 140 return prev; 141 } 142 } 143 lambdaForms[which] = new SoftReference<>(form); 144 return form; 145 } 146 147 /** 148 * Build an MTF for a given type, which must have all references erased to Object. 149 * This MTF will stand for that type and all un-erased variations. 150 * Eagerly compute some basic properties of the type, common to all variations. 151 */ 152 @SuppressWarnings({"rawtypes", "unchecked"}) 153 protected MethodTypeForm(MethodType erasedType) { 154 this.erasedType = erasedType; 155 156 Class<?>[] ptypes = erasedType.ptypes(); 157 int ptypeCount = ptypes.length; 158 int pslotCount = ptypeCount; // temp. estimate 159 int rtypeCount = 1; // temp. estimate 160 int rslotCount = 1; // temp. estimate 161 162 int[] argToSlotTab = null, slotToArgTab = null; 163 164 // Walk the argument types, looking for primitives. 165 int pac = 0, lac = 0, prc = 0, lrc = 0; 166 Class<?>[] epts = ptypes; 167 Class<?>[] bpts = epts; 168 for (int i = 0; i < epts.length; i++) { 169 Class<?> pt = epts[i]; 170 if (pt != Object.class) { 171 ++pac; 172 Wrapper w = Wrapper.forPrimitiveType(pt); 173 if (w.isDoubleWord()) ++lac; 174 if (w.isSubwordOrInt() && pt != int.class) { 175 if (bpts == epts) 176 bpts = bpts.clone(); 177 bpts[i] = int.class; 178 } 179 } 180 } 181 pslotCount += lac; // #slots = #args + #longs 182 Class<?> rt = erasedType.returnType(); 183 Class<?> bt = rt; 184 if (rt != Object.class) { 185 ++prc; // even void.class counts as a prim here 186 Wrapper w = Wrapper.forPrimitiveType(rt); 187 if (w.isDoubleWord()) ++lrc; 188 if (w.isSubwordOrInt() && rt != int.class) 189 bt = int.class; 190 // adjust #slots, #args 191 if (rt == void.class) 192 rtypeCount = rslotCount = 0; 193 else 194 rslotCount += lrc; 195 } 196 if (epts == bpts && bt == rt) { 197 this.basicType = erasedType; 198 } else { 199 this.basicType = MethodType.makeImpl(bt, bpts, true); 200 // fill in rest of data from the basic type: 201 MethodTypeForm that = this.basicType.form(); 202 assert(this != that); 203 this.primCounts = that.primCounts; 204 this.argCounts = that.argCounts; 205 this.argToSlotTable = that.argToSlotTable; 206 this.slotToArgTable = that.slotToArgTable; 207 this.methodHandles = null; 208 this.lambdaForms = null; 209 return; 210 } 211 if (lac != 0) { 212 int slot = ptypeCount + lac; 213 slotToArgTab = new int[slot+1]; 214 argToSlotTab = new int[1+ptypeCount]; 215 argToSlotTab[0] = slot; // argument "-1" is past end of slots 216 for (int i = 0; i < epts.length; i++) { 217 Class<?> pt = epts[i]; 218 Wrapper w = Wrapper.forBasicType(pt); 219 if (w.isDoubleWord()) --slot; 220 --slot; 221 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 222 argToSlotTab[1+i] = slot; 223 } 224 assert(slot == 0); // filled the table 225 } else if (pac != 0) { 226 // have primitives but no long primitives; share slot counts with generic 227 assert(ptypeCount == pslotCount); 228 MethodTypeForm that = MethodType.genericMethodType(ptypeCount).form(); 229 assert(this != that); 230 slotToArgTab = that.slotToArgTable; 231 argToSlotTab = that.argToSlotTable; 232 } else { 233 int slot = ptypeCount; // first arg is deepest in stack 234 slotToArgTab = new int[slot+1]; 235 argToSlotTab = new int[1+ptypeCount]; 236 argToSlotTab[0] = slot; // argument "-1" is past end of slots 237 for (int i = 0; i < ptypeCount; i++) { 238 --slot; 239 slotToArgTab[slot] = i+1; // "+1" see argSlotToParameter note 240 argToSlotTab[1+i] = slot; 241 } 242 } 243 this.primCounts = pack(lrc, prc, lac, pac); 244 this.argCounts = pack(rslotCount, rtypeCount, pslotCount, ptypeCount); 245 this.argToSlotTable = argToSlotTab; 246 this.slotToArgTable = slotToArgTab; 247 248 if (pslotCount >= 256) throw newIllegalArgumentException("too many arguments"); 249 250 // Initialize caches, but only for basic types 251 assert(basicType == erasedType); 252 this.lambdaForms = new SoftReference[LF_LIMIT]; 253 this.methodHandles = new SoftReference[MH_LIMIT]; 254 } 255 256 private static long pack(int a, int b, int c, int d) { 257 assert(((a|b|c|d) & ~0xFFFF) == 0); 258 long hw = ((a << 16) | b), lw = ((c << 16) | d); 259 return (hw << 32) | lw; 260 } 261 private static char unpack(long packed, int word) { // word==0 => return a, ==3 => return d 262 assert(word <= 3); 263 return (char)(packed >> ((3-word) * 16)); 264 } 265 266 public int parameterCount() { // # outgoing values 267 return unpack(argCounts, 3); 268 } 269 public int parameterSlotCount() { // # outgoing interpreter slots 270 return unpack(argCounts, 2); 271 } 272 public int returnCount() { // = 0 (V), or 1 273 return unpack(argCounts, 1); 274 } 275 public int returnSlotCount() { // = 0 (V), 2 (J/D), or 1 276 return unpack(argCounts, 0); 277 } 278 public int primitiveParameterCount() { 279 return unpack(primCounts, 3); 280 } 281 public int longPrimitiveParameterCount() { 282 return unpack(primCounts, 2); 283 } 284 public int primitiveReturnCount() { // = 0 (obj), or 1 285 return unpack(primCounts, 1); 286 } 287 public int longPrimitiveReturnCount() { // = 1 (J/D), or 0 288 return unpack(primCounts, 0); 289 } 290 public boolean hasPrimitives() { 291 return primCounts != 0; 292 } 293 public boolean hasNonVoidPrimitives() { 294 if (primCounts == 0) return false; 295 if (primitiveParameterCount() != 0) return true; 296 return (primitiveReturnCount() != 0 && returnCount() != 0); 297 } 298 public boolean hasLongPrimitives() { 299 return (longPrimitiveParameterCount() | longPrimitiveReturnCount()) != 0; 300 } 301 public int parameterToArgSlot(int i) { 302 return argToSlotTable[1+i]; 303 } 304 public int argSlotToParameter(int argSlot) { 305 // Note: Empty slots are represented by zero in this table. 306 // Valid arguments slots contain incremented entries, so as to be non-zero. 307 // We return -1 the caller to mean an empty slot. 308 return slotToArgTable[argSlot] - 1; 309 } 310 311 static MethodTypeForm findForm(MethodType mt) { 312 MethodType erased = canonicalize(mt, ERASE, ERASE); 313 if (erased == null) { 314 // It is already erased. Make a new MethodTypeForm. 315 return new MethodTypeForm(mt); 316 } else { 317 // Share the MethodTypeForm with the erased version. 318 return erased.form(); 319 } 320 } 321 322 /** Codes for {@link #canonicalize(java.lang.Class, int)}. 323 * ERASE means change every reference to {@code Object}. 324 * WRAP means convert primitives (including {@code void} to their 325 * corresponding wrapper types. UNWRAP means the reverse of WRAP. 326 * INTS means convert all non-void primitive types to int or long, 327 * according to size. LONGS means convert all non-void primitives 328 * to long, regardless of size. RAW_RETURN means convert a type 329 * (assumed to be a return type) to int if it is smaller than an int, 330 * or if it is void. 331 */ 332 public static final int NO_CHANGE = 0, ERASE = 1, WRAP = 2, UNWRAP = 3, INTS = 4, LONGS = 5, RAW_RETURN = 6; 333 334 /** Canonicalize the types in the given method type. 335 * If any types change, intern the new type, and return it. 336 * Otherwise return null. 337 */ 338 public static MethodType canonicalize(MethodType mt, int howRet, int howArgs) { 339 Class<?>[] ptypes = mt.ptypes(); 340 Class<?>[] ptc = MethodTypeForm.canonicalizeAll(ptypes, howArgs); 341 Class<?> rtype = mt.returnType(); 342 Class<?> rtc = MethodTypeForm.canonicalize(rtype, howRet); 343 if (ptc == null && rtc == null) { 344 // It is already canonical. 345 return null; 346 } 347 // Find the erased version of the method type: 348 if (rtc == null) rtc = rtype; 349 if (ptc == null) ptc = ptypes; 350 return MethodType.makeImpl(rtc, ptc, true); 351 } 352 353 /** Canonicalize the given return or param type. 354 * Return null if the type is already canonicalized. 355 */ 356 static Class<?> canonicalize(Class<?> t, int how) { 357 Class<?> ct; 358 if (t == Object.class) { 359 // no change, ever 360 } else if (!t.isPrimitive()) { 361 switch (how) { 362 case UNWRAP: 363 ct = Wrapper.asPrimitiveType(t); 364 if (ct != t) return ct; 365 break; 366 case RAW_RETURN: 367 case ERASE: 368 return Object.class; 369 } 370 } else if (t == void.class) { 371 // no change, usually 372 switch (how) { 373 case RAW_RETURN: 374 return int.class; 375 case WRAP: 376 return Void.class; 377 } 378 } else { 379 // non-void primitive 380 switch (how) { 381 case WRAP: 382 return Wrapper.asWrapperType(t); 383 case INTS: 384 if (t == int.class || t == long.class) 385 return null; // no change 386 if (t == double.class) 387 return long.class; 388 return int.class; 389 case LONGS: 390 if (t == long.class) 391 return null; // no change 392 return long.class; 393 case RAW_RETURN: 394 if (t == int.class || t == long.class || 395 t == float.class || t == double.class) 396 return null; // no change 397 // everything else returns as an int 398 return int.class; 399 } 400 } 401 // no change; return null to signify 402 return null; 403 } 404 405 /** Canonicalize each param type in the given array. 406 * Return null if all types are already canonicalized. 407 */ 408 static Class<?>[] canonicalizeAll(Class<?>[] ts, int how) { 409 Class<?>[] cs = null; 410 for (int imax = ts.length, i = 0; i < imax; i++) { 411 Class<?> c = canonicalize(ts[i], how); 412 if (c == void.class) 413 c = null; // a Void parameter was unwrapped to void; ignore 414 if (c != null) { 415 if (cs == null) 416 cs = ts.clone(); 417 cs[i] = c; 418 } 419 } 420 return cs; 421 } 422 423 @Override 424 public String toString() { 425 return "Form"+erasedType; 426 } 427} 428