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 /** Fetch the vmtarget field.
65 * It will be sanitized as necessary to avoid exposing non-Java references.
66 * This routine is for debugging and reflection.
67 */
68 static native Object getTarget(MethodHandle self, int format);
69
70 /** Fetch the name of the handled method, if available.
71 * This routine is for debugging and reflection.
72 */
73 static MemberName getMethodName(MethodHandle self) {
74 return (MemberName) getTarget(self, ETF_METHOD_NAME);
75 }
76
77 /** Fetch the reflective version of the handled method, if available.
78 */
79 static AccessibleObject getTargetMethod(MethodHandle self) {
80 return (AccessibleObject) getTarget(self, ETF_REFLECT_METHOD);
81 }
82
83 /** Fetch the target of this method handle.
84 * If it directly targets a method, return a MemberName for the method.
85 * If it is chained to another method handle, return that handle.
86 */
87 static Object getTargetInfo(MethodHandle self) {
88 return getTarget(self, ETF_HANDLE_OR_METHOD_NAME);
89 }
90
91 static Object[] makeTarget(Class<?> defc, String name, String sig, int mods, Class<?> refc) {
92 return new Object[] { defc, name, sig, mods, refc };
93 }
94
95 /** Fetch MH-related JVM parameter.
96 * which=0 retrieves MethodHandlePushLimit
97 * which=1 retrieves stack slot push size (in address units)
98 */
99 static native int getConstant(int which);
100
101 /** Java copy of MethodHandlePushLimit in range 2..255. */
102 static final int JVM_PUSH_LIMIT;
103 /** JVM stack motion (in words) after one slot is pushed, usually -1.
104 */
105 static final int JVM_STACK_MOVE_UNIT;
106
107 /** Which conv-ops are implemented by the JVM? */
108 static final int CONV_OP_IMPLEMENTED_MASK;
109 /** Derived mode flag. Only false on some old JVM implementations. */
110 static final boolean HAVE_RICOCHET_FRAMES;
111
112 static final int OP_ROT_ARGS_DOWN_LIMIT_BIAS;
113
114 static final boolean COUNT_GWT;
115
116 /// CallSite support
117
118 /** Tell the JVM that we need to change the target of a CallSite. */
119 static native void setCallSiteTargetNormal(CallSite site, MethodHandle target);
120 static native void setCallSiteTargetVolatile(CallSite site, MethodHandle target);
121
122 private static native void registerNatives();
123 static {
124 registerNatives();
125 int k;
126 JVM_PUSH_LIMIT = getConstant(Constants.GC_JVM_PUSH_LIMIT);
127 JVM_STACK_MOVE_UNIT = getConstant(Constants.GC_JVM_STACK_MOVE_UNIT);
128 k = getConstant(Constants.GC_CONV_OP_IMPLEMENTED_MASK);
129 CONV_OP_IMPLEMENTED_MASK = (k != 0) ? k : DEFAULT_CONV_OP_IMPLEMENTED_MASK;
130 k = getConstant(Constants.GC_OP_ROT_ARGS_DOWN_LIMIT_BIAS);
131 OP_ROT_ARGS_DOWN_LIMIT_BIAS = (k != 0) ? (byte)k : -1;
132 HAVE_RICOCHET_FRAMES = (CONV_OP_IMPLEMENTED_MASK & (1<<OP_COLLECT_ARGS)) != 0;
133 COUNT_GWT = getConstant(Constants.GC_COUNT_GWT) != 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 GC_COUNT_GWT = 4;
148 static final int
149 ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method)
150 ETF_DIRECT_HANDLE = 1, // ultimate method handle (will be a DMH, may be self)
151 ETF_METHOD_NAME = 2, // ultimate method as MemberName
152 ETF_REFLECT_METHOD = 3; // ultimate method as java.lang.reflect object (sans refClass)
153
154 // MemberName
155 // The JVM uses values of -2 and above for vtable indexes.
156 // Field values are simple positive offsets.
157 // Ref: src/share/vm/oops/methodOop.hpp
158 // This value is negative enough to avoid such numbers,
159 // but not too negative.
160 static final int
161 MN_IS_METHOD = 0x00010000, // method (not constructor)
162 MN_IS_CONSTRUCTOR = 0x00020000, // constructor
163 MN_IS_FIELD = 0x00040000, // field
164 MN_IS_TYPE = 0x00080000, // nested type
165 MN_SEARCH_SUPERCLASSES = 0x00100000, // for MHN.getMembers
166 MN_SEARCH_INTERFACES = 0x00200000, // for MHN.getMembers
167 VM_INDEX_UNINITIALIZED = -99;
168
169 // BoundMethodHandle
170 /** Constants for decoding the vmargslot field, which contains 2 values. */
171 static final int
172 ARG_SLOT_PUSH_SHIFT = 16,
173 ARG_SLOT_MASK = (1<<ARG_SLOT_PUSH_SHIFT)-1;
174
175 // AdapterMethodHandle
176 /** Conversions recognized by the JVM.
177 * They must align with the constants in java.lang.invoke.AdapterMethodHandle,
178 * in the JVM file hotspot/src/share/vm/classfile/javaClasses.hpp.
179 */
180 static final int
181 OP_RETYPE_ONLY = 0x0, // no argument changes; straight retype
182 OP_RETYPE_RAW = 0x1, // straight retype, trusted (void->int, Object->T)
183 OP_CHECK_CAST = 0x2, // ref-to-ref conversion; requires a Class argument
184 OP_PRIM_TO_PRIM = 0x3, // converts from one primitive to another
185 OP_REF_TO_PRIM = 0x4, // unboxes a wrapper to produce a primitive
186 OP_PRIM_TO_REF = 0x5, // boxes a primitive into a wrapper
187 OP_SWAP_ARGS = 0x6, // swap arguments (vminfo is 2nd arg)
188 OP_ROT_ARGS = 0x7, // rotate arguments (vminfo is displaced arg)
189 OP_DUP_ARGS = 0x8, // duplicates one or more arguments (at TOS)
190 OP_DROP_ARGS = 0x9, // remove one or more argument slots
191 OP_COLLECT_ARGS = 0xA, // combine arguments using an auxiliary function
192 OP_SPREAD_ARGS = 0xB, // expand in place a varargs array (of known size)
193 OP_FOLD_ARGS = 0xC, // combine but do not remove arguments; prepend result
194 //OP_UNUSED_13 = 0xD, // unused code, perhaps for reified argument lists
195 CONV_OP_LIMIT = 0xE; // limit of CONV_OP enumeration
196 /** Shift and mask values for decoding the AMH.conversion field.
197 * These numbers are shared with the JVM for creating AMHs.
198 */
199 static final int
200 CONV_OP_MASK = 0xF00, // this nybble contains the conversion op field
201 CONV_TYPE_MASK = 0x0F, // fits T_ADDRESS and below
202 CONV_VMINFO_MASK = 0x0FF, // LSB is reserved for JVM use
203 CONV_VMINFO_SHIFT = 0, // position of bits in CONV_VMINFO_MASK
204 CONV_OP_SHIFT = 8, // position of bits in CONV_OP_MASK
205 CONV_DEST_TYPE_SHIFT = 12, // byte 2 has the adapter BasicType (if needed)
206 CONV_SRC_TYPE_SHIFT = 16, // byte 2 has the source BasicType (if needed)
207 CONV_STACK_MOVE_SHIFT = 20, // high 12 bits give signed SP change
208 CONV_STACK_MOVE_MASK = (1 << (32 - CONV_STACK_MOVE_SHIFT)) - 1;
209
210 /** Which conv-ops are implemented by the JVM? */
211 static final int DEFAULT_CONV_OP_IMPLEMENTED_MASK =
212 // Value to use if the corresponding JVM query fails.
213 ((1<<OP_RETYPE_ONLY)
214 |(1<<OP_RETYPE_RAW)
215 |(1<<OP_CHECK_CAST)
216 |(1<<OP_PRIM_TO_PRIM)
217 |(1<<OP_REF_TO_PRIM)
218 |(1<<OP_SWAP_ARGS)
219 |(1<<OP_ROT_ARGS)
220 |(1<<OP_DUP_ARGS)
221 |(1<<OP_DROP_ARGS)
222 //|(1<<OP_SPREAD_ARGS)
223 );
224
225 /**
226 * Basic types as encoded in the JVM. These code values are not
227 * intended for use outside this class. They are used as part of
228 * a private interface between the JVM and this class.
229 */
230 static final int
231 T_BOOLEAN = 4,
232 T_CHAR = 5,
233 T_FLOAT = 6,
234 T_DOUBLE = 7,
235 T_BYTE = 8,
236 T_SHORT = 9,
237 T_INT = 10,
238 T_LONG = 11,
239 T_OBJECT = 12,
240 //T_ARRAY = 13
241 T_VOID = 14,
242 //T_ADDRESS = 15
243 T_ILLEGAL = 99;
244
245 /**
246 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries.
247 */
248 static final int
249 REF_getField = 1,
250 REF_getStatic = 2,
251 REF_putField = 3,
252 REF_putStatic = 4,
253 REF_invokeVirtual = 5,
254 REF_invokeStatic = 6,
255 REF_invokeSpecial = 7,
256 REF_newInvokeSpecial = 8,
257 REF_invokeInterface = 9;
258 }
259
260 private static native int getNamedCon(int which, Object[] name);
261 static boolean verifyConstants() {
262 Object[] box = { null };
263 for (int i = 0; ; i++) {
264 box[0] = null;
265 int vmval = getNamedCon(i, box);
266 if (box[0] == null) break;
267 String name = (String) box[0];
268 try {
269 Field con = Constants.class.getDeclaredField(name);
270 int jval = con.getInt(null);
271 if (jval == vmval) continue;
272 String err = (name+": JVM has "+vmval+" while Java has "+jval);
273 if (name.equals("CONV_OP_LIMIT")) {
274 System.err.println("warning: "+err);
275 continue;
276 }
277 throw new InternalError(err);
278 } catch (Exception ex) {
279 if (ex instanceof NoSuchFieldException) {
280 String err = (name+": JVM has "+vmval+" which Java does not define");
281 // ignore exotic ops the JVM cares about; we just wont issue them
282 if (name.startsWith("OP_") || name.startsWith("GC_")) {
283 System.err.println("warning: "+err);
284 continue;
285 }
286 }
287 throw new InternalError(name+": access failed, got "+ex);
288 }
289 }
290 return true;
291 }
292 static {
293 assert(verifyConstants());
294 }
295
296 // Up-calls from the JVM.
297 // These must NOT be public.
298
299 /**
300 * The JVM is linking an invokedynamic instruction. Create a reified call site for it.
301 */
302 static CallSite makeDynamicCallSite(MethodHandle bootstrapMethod,
303 String name, MethodType type,
304 Object info,
305 MemberName callerMethod, int callerBCI) {
306 return CallSite.makeSite(bootstrapMethod, name, type, info, callerMethod, callerBCI);
307 }
308
309 /**
310 * Called by the JVM to check the length of a spread array.
311 */
312 static void checkSpreadArgument(Object av, int n) {
313 MethodHandleStatics.checkSpreadArgument(av, n);
314 }
315
316 /**
317 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one.
318 */
319 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) {
320 return MethodType.makeImpl(rtype, ptypes, true);
321 }
322
323 /**
324 * The JVM wants to use a MethodType with inexact invoke. Give the runtime fair warning.
325 */
326 static void notifyGenericMethodType(MethodType type) {
327 type.form().notifyGenericMethodType();
328 }
329
330 /**
331 * The JVM wants to raise an exception. Here's the path.
332 */
333 static void raiseException(int code, Object actual, Object required) {
334 String message = null;
335 switch (code) {
336 case 190: // arraylength
337 try {
338 String reqLength = "";
339 if (required instanceof AdapterMethodHandle) {
340 int conv = ((AdapterMethodHandle)required).getConversion();
341 int spChange = AdapterMethodHandle.extractStackMove(conv);
342 reqLength = " of length "+(spChange+1);
343 }
344 int actualLength = actual == null ? 0 : java.lang.reflect.Array.getLength(actual);
345 message = "required array"+reqLength+", but encountered wrong length "+actualLength;
346 break;
347 } catch (IllegalArgumentException ex) {
348 }
349 required = Object[].class; // should have been an array
350 code = 192; // checkcast
351 break;
352 case 191: // athrow
353 // JVM is asking us to wrap an exception which happened during resolving
354 if (required == BootstrapMethodError.class) {
355 throw new BootstrapMethodError((Throwable) actual);
356 }
357 break;
358 }
359 // disregard the identity of the actual object, if it is not a class:
360 if (message == null) {
361 if (!(actual instanceof Class) && !(actual instanceof MethodType))
362 actual = actual.getClass();
363 if (actual != null)
364 message = "required "+required+" but encountered "+actual;
365 else
366 message = "required "+required;
367 }
368 switch (code) {
369 case 190: // arraylength
370 throw new ArrayIndexOutOfBoundsException(message);
371 case 50: //_aaload
372 throw new ClassCastException(message);
373 case 192: // checkcast
374 throw new ClassCastException(message);
375 default:
376 throw new InternalError("unexpected code "+code+": "+message);
377 }
378 }
379
380 /**
381 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help.
382 * It will make an up-call to this method. (Do not change the name or signature.)
383 */
384 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
385 Class<?> defc, String name, Object type) {
386 try {
387 Lookup lookup = IMPL_LOOKUP.in(callerClass);
388 return lookup.linkMethodHandleConstant(refKind, defc, name, type);
389 } catch (ReflectiveOperationException ex) {
390 Error err = new IncompatibleClassChangeError();
391 err.initCause(ex);
392 throw err;
393 }
394 }
395 }