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 static final boolean COUNT_GWT;
124
125 private static native void registerNatives();
126 static {
127 registerNatives();
128 int k;
129 JVM_PUSH_LIMIT = getConstant(Constants.GC_JVM_PUSH_LIMIT);
130 JVM_STACK_MOVE_UNIT = getConstant(Constants.GC_JVM_STACK_MOVE_UNIT);
131 k = getConstant(Constants.GC_CONV_OP_IMPLEMENTED_MASK);
132 CONV_OP_IMPLEMENTED_MASK = (k != 0) ? k : DEFAULT_CONV_OP_IMPLEMENTED_MASK;
133 k = getConstant(Constants.GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS);
134 OP_ROT_ARGS_DOWN_LIMIT_BIAS = (k != 0) ? (byte)k : -1;
135 HAVE_RICOCHET_FRAMES = (CONV_OP_IMPLEMENTED_MASK & (1<<OP_COLLECT_ARGS)) != 0;
136 COUNT_GWT = getConstant(Constants.GC_COUNT_GWT) != 0;
137 //sun.reflect.Reflection.registerMethodsToFilter(MethodHandleImpl.class, "init");
138 }
139
140 // All compile-time constants go here.
141 // There is an opportunity to check them against the JVM's idea of them.
142 static class Constants {
143 Constants() { } // static only
144 // MethodHandleImpl
145 static final int // for getConstant
146 GC_JVM_PUSH_LIMIT = 0,
147 GC_JVM_STACK_MOVE_UNIT = 1,
148 GC_CONV_OP_IMPLEMENTED_MASK = 2,
149 GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS = 3,
150 GC_COUNT_GWT = 4;
151 static final int
152 ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method)
153 ETF_DIRECT_HANDLE = 1, // ultimate method handle (will be a DMH, may be self)
154 ETF_METHOD_NAME = 2, // ultimate method as MemberName
155 ETF_REFLECT_METHOD = 3; // ultimate method as java.lang.reflect object (sans refClass)
156
157 // MemberName
158 // The JVM uses values of -2 and above for vtable indexes.
159 // Field values are simple positive offsets.
160 // Ref: src/share/vm/oops/methodOop.hpp
161 // This value is negative enough to avoid such numbers,
162 // but not too negative.
163 static final int
164 MN_IS_METHOD = 0x00010000, // method (not constructor)
165 MN_IS_CONSTRUCTOR = 0x00020000, // constructor
166 MN_IS_FIELD = 0x00040000, // field
167 MN_IS_TYPE = 0x00080000, // nested type
168 MN_SEARCH_SUPERCLASSES = 0x00100000, // for MHN.getMembers
169 MN_SEARCH_INTERFACES = 0x00200000, // for MHN.getMembers
170 VM_INDEX_UNINITIALIZED = -99;
171
172 // BoundMethodHandle
173 /** Constants for decoding the vmargslot field, which contains 2 values. */
174 static final int
175 ARG_SLOT_PUSH_SHIFT = 16,
176 ARG_SLOT_MASK = (1<<ARG_SLOT_PUSH_SHIFT)-1;
177
178 // AdapterMethodHandle
179 /** Conversions recognized by the JVM.
180 * They must align with the constants in java.lang.invoke.AdapterMethodHandle,
181 * in the JVM file hotspot/src/share/vm/classfile/javaClasses.hpp.
182 */
183 static final int
184 OP_RETYPE_ONLY = 0x0, // no argument changes; straight retype
185 OP_RETYPE_RAW = 0x1, // straight retype, trusted (void->int, Object->T)
186 OP_CHECK_CAST = 0x2, // ref-to-ref conversion; requires a Class argument
187 OP_PRIM_TO_PRIM = 0x3, // converts from one primitive to another
188 OP_REF_TO_PRIM = 0x4, // unboxes a wrapper to produce a primitive
189 OP_PRIM_TO_REF = 0x5, // boxes a primitive into a wrapper
190 OP_SWAP_ARGS = 0x6, // swap arguments (vminfo is 2nd arg)
191 OP_ROT_ARGS = 0x7, // rotate arguments (vminfo is displaced arg)
192 OP_DUP_ARGS = 0x8, // duplicates one or more arguments (at TOS)
193 OP_DROP_ARGS = 0x9, // remove one or more argument slots
194 OP_COLLECT_ARGS = 0xA, // combine arguments using an auxiliary function
195 OP_SPREAD_ARGS = 0xB, // expand in place a varargs array (of known size)
196 OP_FOLD_ARGS = 0xC, // combine but do not remove arguments; prepend result
197 //OP_UNUSED_13 = 0xD, // unused code, perhaps for reified argument lists
198 CONV_OP_LIMIT = 0xE; // limit of CONV_OP enumeration
199 /** Shift and mask values for decoding the AMH.conversion field.
200 * These numbers are shared with the JVM for creating AMHs.
201 */
202 static final int
203 CONV_OP_MASK = 0xF00, // this nybble contains the conversion op field
204 CONV_TYPE_MASK = 0x0F, // fits T_ADDRESS and below
205 CONV_VMINFO_MASK = 0x0FF, // LSB is reserved for JVM use
206 CONV_VMINFO_SHIFT = 0, // position of bits in CONV_VMINFO_MASK
207 CONV_OP_SHIFT = 8, // position of bits in CONV_OP_MASK
208 CONV_DEST_TYPE_SHIFT = 12, // byte 2 has the adapter BasicType (if needed)
209 CONV_SRC_TYPE_SHIFT = 16, // byte 2 has the source BasicType (if needed)
210 CONV_STACK_MOVE_SHIFT = 20, // high 12 bits give signed SP change
211 CONV_STACK_MOVE_MASK = (1 << (32 - CONV_STACK_MOVE_SHIFT)) - 1;
212
213 /** Which conv-ops are implemented by the JVM? */
214 static final int DEFAULT_CONV_OP_IMPLEMENTED_MASK =
215 // Value to use if the corresponding JVM query fails.
216 ((1<<OP_RETYPE_ONLY)
217 |(1<<OP_RETYPE_RAW)
218 |(1<<OP_CHECK_CAST)
219 |(1<<OP_PRIM_TO_PRIM)
220 |(1<<OP_REF_TO_PRIM)
221 |(1<<OP_SWAP_ARGS)
222 |(1<<OP_ROT_ARGS)
223 |(1<<OP_DUP_ARGS)
224 |(1<<OP_DROP_ARGS)
225 //|(1<<OP_SPREAD_ARGS)
226 );
227
228 /**
229 * Basic types as encoded in the JVM. These code values are not
230 * intended for use outside this class. They are used as part of
231 * a private interface between the JVM and this class.
232 */
233 static final int
234 T_BOOLEAN = 4,
235 T_CHAR = 5,
236 T_FLOAT = 6,
237 T_DOUBLE = 7,
238 T_BYTE = 8,
239 T_SHORT = 9,
240 T_INT = 10,
241 T_LONG = 11,
242 T_OBJECT = 12,
243 //T_ARRAY = 13
244 T_VOID = 14,
245 //T_ADDRESS = 15
246 T_ILLEGAL = 99;
247
248 /**
249 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries.
250 */
251 static final int
252 REF_getField = 1,
253 REF_getStatic = 2,
254 REF_putField = 3,
255 REF_putStatic = 4,
256 REF_invokeVirtual = 5,
257 REF_invokeStatic = 6,
258 REF_invokeSpecial = 7,
259 REF_newInvokeSpecial = 8,
260 REF_invokeInterface = 9;
261 }
262
263 private static native int getNamedCon(int which, Object[] name);
264 static boolean verifyConstants() {
265 Object[] box = { null };
266 for (int i = 0; ; i++) {
267 box[0] = null;
268 int vmval = getNamedCon(i, box);
269 if (box[0] == null) break;
270 String name = (String) box[0];
271 try {
272 Field con = Constants.class.getDeclaredField(name);
273 int jval = con.getInt(null);
274 if (jval == vmval) continue;
275 String err = (name+": JVM has "+vmval+" while Java has "+jval);
276 if (name.equals("CONV_OP_LIMIT")) {
277 System.err.println("warning: "+err);
278 continue;
279 }
280 throw new InternalError(err);
281 } catch (Exception ex) {
282 if (ex instanceof NoSuchFieldException) {
283 String err = (name+": JVM has "+vmval+" which Java does not define");
284 // ignore exotic ops the JVM cares about; we just wont issue them
285 if (name.startsWith("OP_") || name.startsWith("GC_")) {
286 System.err.println("warning: "+err);
287 continue;
288 }
289 }
290 throw new InternalError(name+": access failed, got "+ex);
291 }
292 }
293 return true;
294 }
295 static {
296 assert(verifyConstants());
297 }
298
299 // Up-calls from the JVM.
300 // These must NOT be public.
301
302 /**
303 * The JVM is linking an invokedynamic instruction. Create a reified call site for it.
304 */
305 static CallSite makeDynamicCallSite(MethodHandle bootstrapMethod,
306 String name, MethodType type,
307 Object info,
308 MemberName callerMethod, int callerBCI) {
309 return CallSite.makeSite(bootstrapMethod, name, type, info, callerMethod, callerBCI);
310 }
311
312 /**
313 * Called by the JVM to check the length of a spread array.
314 */
315 static void checkSpreadArgument(Object av, int n) {
316 MethodHandleStatics.checkSpreadArgument(av, n);
317 }
318
319 /**
320 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one.
321 */
322 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) {
323 return MethodType.makeImpl(rtype, ptypes, true);
324 }
325
326 /**
327 * The JVM wants to use a MethodType with inexact invoke. Give the runtime fair warning.
328 */
329 static void notifyGenericMethodType(MethodType type) {
330 type.form().notifyGenericMethodType();
331 }
332
333 /**
334 * The JVM wants to raise an exception. Here's the path.
335 */
336 static void raiseException(int code, Object actual, Object required) {
337 String message = null;
338 switch (code) {
339 case 190: // arraylength
340 try {
341 String reqLength = "";
342 if (required instanceof AdapterMethodHandle) {
343 int conv = ((AdapterMethodHandle)required).getConversion();
344 int spChange = AdapterMethodHandle.extractStackMove(conv);
345 reqLength = " of length "+(spChange+1);
346 }
347 int actualLength = actual == null ? 0 : java.lang.reflect.Array.getLength(actual);
348 message = "required array"+reqLength+", but encountered wrong length "+actualLength;
349 break;
350 } catch (IllegalArgumentException ex) {
351 }
352 required = Object[].class; // should have been an array
353 code = 192; // checkcast
354 break;
355 case 191: // athrow
356 // JVM is asking us to wrap an exception which happened during resolving
357 if (required == BootstrapMethodError.class) {
358 throw new BootstrapMethodError((Throwable) actual);
359 }
360 break;
361 }
362 // disregard the identity of the actual object, if it is not a class:
363 if (message == null) {
364 if (!(actual instanceof Class) && !(actual instanceof MethodType))
365 actual = actual.getClass();
366 if (actual != null)
367 message = "required "+required+" but encountered "+actual;
368 else
369 message = "required "+required;
370 }
371 switch (code) {
372 case 190: // arraylength
373 throw new ArrayIndexOutOfBoundsException(message);
374 case 50: //_aaload
375 throw new ClassCastException(message);
376 case 192: // checkcast
377 throw new ClassCastException(message);
378 default:
379 throw new InternalError("unexpected code "+code+": "+message);
380 }
381 }
382
383 /**
384 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help.
385 * It will make an up-call to this method. (Do not change the name or signature.)
386 */
387 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
388 Class<?> defc, String name, Object type) {
389 try {
390 Lookup lookup = IMPL_LOOKUP.in(callerClass);
391 return lookup.linkMethodHandleConstant(refKind, defc, name, type);
392 } catch (ReflectiveOperationException ex) {
393 Error err = new IncompatibleClassChangeError();
394 err.initCause(ex);
395 throw err;
396 }
397 }
398 }