1 /* 2 * Copyright (c) 2008, 2011, 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 java.lang.invoke.MethodHandles.Lookup; 29 import java.lang.reflect.AccessibleObject; 30 import java.lang.reflect.Field; 31 import static java.lang.invoke.MethodHandleNatives.Constants.*; 32 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP; 33 34 /** 35 * The JVM interface for the method handles package is all here. 36 * This is an interface internal and private to an implemetantion of JSR 292. 37 * <em>This class is not part of the JSR 292 standard.</em> 38 * @author jrose 39 */ 40 class MethodHandleNatives { 41 42 private MethodHandleNatives() { } // static only 43 44 /// MethodName support 45 46 static native void init(MemberName self, Object ref); 47 static native void expand(MemberName self); 48 static native void resolve(MemberName self, Class<?> caller); 49 static native int getMembers(Class<?> defc, String matchName, String matchSig, 50 int matchFlags, Class<?> caller, int skip, MemberName[] results); 51 52 /// MethodHandle support 53 54 /** Initialize the method handle to adapt the call. */ 55 static native void init(AdapterMethodHandle self, MethodHandle target, int argnum); 56 /** Initialize the method handle to call the correct method, directly. */ 57 static native void init(BoundMethodHandle self, Object target, int argnum); 58 /** Initialize the method handle to call as if by an invoke* instruction. */ 59 static native void init(DirectMethodHandle self, Object ref, boolean doDispatch, Class<?> caller); 60 61 /** Initialize a method type, once per form. */ 62 static native void init(MethodType self); 63 64 /** Tell the JVM about a class's bootstrap method. */ 65 static native void registerBootstrap(Class<?> caller, MethodHandle bootstrapMethod); 66 67 /** Ask the JVM about a class's bootstrap method. */ 68 static native MethodHandle getBootstrap(Class<?> caller); 69 70 /** Tell the JVM that we need to change the target of an invokedynamic. */ 71 static native void setCallSiteTarget(CallSite site, MethodHandle target); 72 73 /** Fetch the vmtarget field. 74 * It will be sanitized as necessary to avoid exposing non-Java references. 75 * This routine is for debugging and reflection. 76 */ 77 static native Object getTarget(MethodHandle self, int format); 78 79 /** Fetch the name of the handled method, if available. 80 * This routine is for debugging and reflection. 81 */ 82 static MemberName getMethodName(MethodHandle self) { 83 return (MemberName) getTarget(self, ETF_METHOD_NAME); 84 } 85 86 /** Fetch the reflective version of the handled method, if available. 87 */ 88 static AccessibleObject getTargetMethod(MethodHandle self) { 89 return (AccessibleObject) getTarget(self, ETF_REFLECT_METHOD); 90 } 91 92 /** Fetch the target of this method handle. 93 * If it directly targets a method, return a MemberName for the method. 94 * If it is chained to another method handle, return that handle. 95 */ 96 static Object getTargetInfo(MethodHandle self) { 97 return getTarget(self, ETF_HANDLE_OR_METHOD_NAME); 98 } 99 100 static Object[] makeTarget(Class<?> defc, String name, String sig, int mods, Class<?> refc) { 101 return new Object[] { defc, name, sig, mods, refc }; 102 } 103 104 /** Fetch MH-related JVM parameter. 105 * which=0 retrieves MethodHandlePushLimit 106 * which=1 retrieves stack slot push size (in address units) 107 */ 108 static native int getConstant(int which); 109 110 /** Java copy of MethodHandlePushLimit in range 2..255. */ 111 static final int JVM_PUSH_LIMIT; 112 /** JVM stack motion (in words) after one slot is pushed, usually -1. 113 */ 114 static final int JVM_STACK_MOVE_UNIT; 115 116 /** Which conv-ops are implemented by the JVM? */ 117 static final int CONV_OP_IMPLEMENTED_MASK; 118 /** Derived mode flag. Only false on some old JVM implementations. */ 119 static final boolean HAVE_RICOCHET_FRAMES; 120 121 static final int OP_ROT_ARGS_DOWN_LIMIT_BIAS; 122 123 private static native void registerNatives(); 124 static { 125 registerNatives(); 126 int k; 127 JVM_PUSH_LIMIT = getConstant(Constants.GC_JVM_PUSH_LIMIT); 128 JVM_STACK_MOVE_UNIT = getConstant(Constants.GC_JVM_STACK_MOVE_UNIT); 129 k = getConstant(Constants.GC_CONV_OP_IMPLEMENTED_MASK); 130 CONV_OP_IMPLEMENTED_MASK = (k != 0) ? k : DEFAULT_CONV_OP_IMPLEMENTED_MASK; 131 k = getConstant(Constants.GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS); 132 OP_ROT_ARGS_DOWN_LIMIT_BIAS = (k != 0) ? (byte)k : -1; 133 HAVE_RICOCHET_FRAMES = (CONV_OP_IMPLEMENTED_MASK & (1<<OP_COLLECT_ARGS)) != 0; 134 //sun.reflect.Reflection.registerMethodsToFilter(MethodHandleImpl.class, "init"); 135 } 136 137 // All compile-time constants go here. 138 // There is an opportunity to check them against the JVM's idea of them. 139 static class Constants { 140 Constants() { } // static only 141 // MethodHandleImpl 142 static final int // for getConstant 143 GC_JVM_PUSH_LIMIT = 0, 144 GC_JVM_STACK_MOVE_UNIT = 1, 145 GC_CONV_OP_IMPLEMENTED_MASK = 2, 146 GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS = 3; 147 static final int 148 ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method) 149 ETF_DIRECT_HANDLE = 1, // ultimate method handle (will be a DMH, may be self) 150 ETF_METHOD_NAME = 2, // ultimate method as MemberName 151 ETF_REFLECT_METHOD = 3; // ultimate method as java.lang.reflect object (sans refClass) 152 153 // MemberName 154 // The JVM uses values of -2 and above for vtable indexes. 155 // Field values are simple positive offsets. 156 // Ref: src/share/vm/oops/methodOop.hpp 157 // This value is negative enough to avoid such numbers, 158 // but not too negative. 159 static final int 160 MN_IS_METHOD = 0x00010000, // method (not constructor) 161 MN_IS_CONSTRUCTOR = 0x00020000, // constructor 162 MN_IS_FIELD = 0x00040000, // field 163 MN_IS_TYPE = 0x00080000, // nested type 164 MN_SEARCH_SUPERCLASSES = 0x00100000, // for MHN.getMembers 165 MN_SEARCH_INTERFACES = 0x00200000, // for MHN.getMembers 166 VM_INDEX_UNINITIALIZED = -99; 167 168 // BoundMethodHandle 169 /** Constants for decoding the vmargslot field, which contains 2 values. */ 170 static final int 171 ARG_SLOT_PUSH_SHIFT = 16, 172 ARG_SLOT_MASK = (1<<ARG_SLOT_PUSH_SHIFT)-1; 173 174 // AdapterMethodHandle 175 /** Conversions recognized by the JVM. 176 * They must align with the constants in java.lang.invoke.AdapterMethodHandle, 177 * in the JVM file hotspot/src/share/vm/classfile/javaClasses.hpp. 178 */ 179 static final int 180 OP_RETYPE_ONLY = 0x0, // no argument changes; straight retype 181 OP_RETYPE_RAW = 0x1, // straight retype, trusted (void->int, Object->T) 182 OP_CHECK_CAST = 0x2, // ref-to-ref conversion; requires a Class argument 183 OP_PRIM_TO_PRIM = 0x3, // converts from one primitive to another 184 OP_REF_TO_PRIM = 0x4, // unboxes a wrapper to produce a primitive 185 OP_PRIM_TO_REF = 0x5, // boxes a primitive into a wrapper 186 OP_SWAP_ARGS = 0x6, // swap arguments (vminfo is 2nd arg) 187 OP_ROT_ARGS = 0x7, // rotate arguments (vminfo is displaced arg) 188 OP_DUP_ARGS = 0x8, // duplicates one or more arguments (at TOS) 189 OP_DROP_ARGS = 0x9, // remove one or more argument slots 190 OP_COLLECT_ARGS = 0xA, // combine arguments using an auxiliary function 191 OP_SPREAD_ARGS = 0xB, // expand in place a varargs array (of known size) 192 OP_FOLD_ARGS = 0xC, // combine but do not remove arguments; prepend result 193 //OP_UNUSED_13 = 0xD, // unused code, perhaps for reified argument lists 194 CONV_OP_LIMIT = 0xE; // limit of CONV_OP enumeration 195 /** Shift and mask values for decoding the AMH.conversion field. 196 * These numbers are shared with the JVM for creating AMHs. 197 */ 198 static final int 199 CONV_OP_MASK = 0xF00, // this nybble contains the conversion op field 200 CONV_TYPE_MASK = 0x0F, // fits T_ADDRESS and below 201 CONV_VMINFO_MASK = 0x0FF, // LSB is reserved for JVM use 202 CONV_VMINFO_SHIFT = 0, // position of bits in CONV_VMINFO_MASK 203 CONV_OP_SHIFT = 8, // position of bits in CONV_OP_MASK 204 CONV_DEST_TYPE_SHIFT = 12, // byte 2 has the adapter BasicType (if needed) 205 CONV_SRC_TYPE_SHIFT = 16, // byte 2 has the source BasicType (if needed) 206 CONV_STACK_MOVE_SHIFT = 20, // high 12 bits give signed SP change 207 CONV_STACK_MOVE_MASK = (1 << (32 - CONV_STACK_MOVE_SHIFT)) - 1; 208 209 /** Which conv-ops are implemented by the JVM? */ 210 static final int DEFAULT_CONV_OP_IMPLEMENTED_MASK = 211 // Value to use if the corresponding JVM query fails. 212 ((1<<OP_RETYPE_ONLY) 213 |(1<<OP_RETYPE_RAW) 214 |(1<<OP_CHECK_CAST) 215 |(1<<OP_PRIM_TO_PRIM) 216 |(1<<OP_REF_TO_PRIM) 217 |(1<<OP_SWAP_ARGS) 218 |(1<<OP_ROT_ARGS) 219 |(1<<OP_DUP_ARGS) 220 |(1<<OP_DROP_ARGS) 221 //|(1<<OP_SPREAD_ARGS) 222 ); 223 224 /** 225 * Basic types as encoded in the JVM. These code values are not 226 * intended for use outside this class. They are used as part of 227 * a private interface between the JVM and this class. 228 */ 229 static final int 230 T_BOOLEAN = 4, 231 T_CHAR = 5, 232 T_FLOAT = 6, 233 T_DOUBLE = 7, 234 T_BYTE = 8, 235 T_SHORT = 9, 236 T_INT = 10, 237 T_LONG = 11, 238 T_OBJECT = 12, 239 //T_ARRAY = 13 240 T_VOID = 14, 241 //T_ADDRESS = 15 242 T_ILLEGAL = 99; 243 244 /** 245 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries. 246 */ 247 static final int 248 REF_getField = 1, 249 REF_getStatic = 2, 250 REF_putField = 3, 251 REF_putStatic = 4, 252 REF_invokeVirtual = 5, 253 REF_invokeStatic = 6, 254 REF_invokeSpecial = 7, 255 REF_newInvokeSpecial = 8, 256 REF_invokeInterface = 9; 257 } 258 259 private static native int getNamedCon(int which, Object[] name); 260 static boolean verifyConstants() { 261 Object[] box = { null }; 262 for (int i = 0; ; i++) { 263 box[0] = null; 264 int vmval = getNamedCon(i, box); 265 if (box[0] == null) break; 266 String name = (String) box[0]; 267 try { 268 Field con = Constants.class.getDeclaredField(name); 269 int jval = con.getInt(null); 270 if (jval == vmval) continue; 271 String err = (name+": JVM has "+vmval+" while Java has "+jval); 272 if (name.equals("CONV_OP_LIMIT")) { 273 System.err.println("warning: "+err); 274 continue; 275 } 276 throw new InternalError(err); 277 } catch (Exception ex) { 278 if (ex instanceof NoSuchFieldException) { 279 String err = (name+": JVM has "+vmval+" which Java does not define"); 280 // ignore exotic ops the JVM cares about; we just wont issue them 281 if (name.startsWith("OP_") || name.startsWith("GC_")) { 282 System.err.println("warning: "+err); 283 continue; 284 } 285 } 286 throw new InternalError(name+": access failed, got "+ex); 287 } 288 } 289 return true; 290 } 291 static { 292 assert(verifyConstants()); 293 } 294 295 // Up-calls from the JVM. 296 // These must NOT be public. 297 298 /** 299 * The JVM is linking an invokedynamic instruction. Create a reified call site for it. 300 */ 301 static CallSite makeDynamicCallSite(MethodHandle bootstrapMethod, 302 String name, MethodType type, 303 Object info, 304 MemberName callerMethod, int callerBCI) { 305 return CallSite.makeSite(bootstrapMethod, name, type, info, callerMethod, callerBCI); 306 } 307 308 /** 309 * Called by the JVM to check the length of a spread array. 310 */ 311 static void checkSpreadArgument(Object av, int n) { 312 MethodHandleStatics.checkSpreadArgument(av, n); 313 } 314 315 /** 316 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one. 317 */ 318 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) { 319 return MethodType.makeImpl(rtype, ptypes, true); 320 } 321 322 /** 323 * The JVM wants to use a MethodType with inexact invoke. Give the runtime fair warning. 324 */ 325 static void notifyGenericMethodType(MethodType type) { 326 type.form().notifyGenericMethodType(); 327 } 328 329 /** 330 * The JVM wants to raise an exception. Here's the path. 331 */ 332 static void raiseException(int code, Object actual, Object required) { 333 String message = null; 334 switch (code) { 335 case 190: // arraylength 336 try { 337 String reqLength = ""; 338 if (required instanceof AdapterMethodHandle) { 339 int conv = ((AdapterMethodHandle)required).getConversion(); 340 int spChange = AdapterMethodHandle.extractStackMove(conv); 341 reqLength = " of length "+(spChange+1); 342 } 343 int actualLength = actual == null ? 0 : java.lang.reflect.Array.getLength(actual); 344 message = "required array"+reqLength+", but encountered wrong length "+actualLength; 345 break; 346 } catch (IllegalArgumentException ex) { 347 } 348 required = Object[].class; // should have been an array 349 code = 192; // checkcast 350 break; 351 case 191: // athrow 352 // JVM is asking us to wrap an exception which happened during resolving 353 if (required == BootstrapMethodError.class) { 354 throw new BootstrapMethodError((Throwable) actual); 355 } 356 break; 357 } 358 // disregard the identity of the actual object, if it is not a class: 359 if (message == null) { 360 if (!(actual instanceof Class) && !(actual instanceof MethodType)) 361 actual = actual.getClass(); 362 if (actual != null) 363 message = "required "+required+" but encountered "+actual; 364 else 365 message = "required "+required; 366 } 367 switch (code) { 368 case 190: // arraylength 369 throw new ArrayIndexOutOfBoundsException(message); 370 case 50: //_aaload 371 throw new ClassCastException(message); 372 case 192: // checkcast 373 throw new ClassCastException(message); 374 default: 375 throw new InternalError("unexpected code "+code+": "+message); 376 } 377 } 378 379 /** 380 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help. 381 * It will make an up-call to this method. (Do not change the name or signature.) 382 */ 383 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind, 384 Class<?> defc, String name, Object type) { 385 try { 386 Lookup lookup = IMPL_LOOKUP.in(callerClass); 387 return lookup.linkMethodHandleConstant(refKind, defc, name, type); 388 } catch (ReflectiveOperationException ex) { 389 Error err = new IncompatibleClassChangeError(); 390 err.initCause(ex); 391 throw err; 392 } 393 } 394 }