1 /*
2 * Copyright (c) 2008, 2012, 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.Field;
30 import static java.lang.invoke.MethodHandleNatives.Constants.*;
31 import static java.lang.invoke.MethodHandleStatics.*;
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 implementation 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 /// MemberName support
45
46 static native void init(MemberName self, Object ref);
47 static native void expand(MemberName self);
48 static native MemberName resolve(MemberName self, Class<?> caller) throws LinkageError;
49 static native int getMembers(Class<?> defc, String matchName, String matchSig,
50 int matchFlags, Class<?> caller, int skip, MemberName[] results);
51
52 /// Field layout queries parallel to sun.misc.Unsafe:
53 static native long objectFieldOffset(MemberName self); // e.g., returns vmindex
54 static native long staticFieldOffset(MemberName self); // e.g., returns vmindex
55 static native Object staticFieldBase(MemberName self); // e.g., returns clazz
56 static native Object getMemberVMInfo(MemberName self); // returns {vmindex,vmtarget}
57
58 /// MethodHandle support
59
60 /** Fetch MH-related JVM parameter.
61 * which=0 retrieves MethodHandlePushLimit
62 * which=1 retrieves stack slot push size (in address units)
63 */
64 static native int getConstant(int which);
65
66 static final boolean COUNT_GWT;
67
68 /// CallSite support
69
70 /** Tell the JVM that we need to change the target of a CallSite. */
71 static native void setCallSiteTargetNormal(CallSite site, MethodHandle target);
72 static native void setCallSiteTargetVolatile(CallSite site, MethodHandle target);
73
74 private static native void registerNatives();
75 static {
76 registerNatives();
77 COUNT_GWT = getConstant(Constants.GC_COUNT_GWT) != 0;
78
79 // The JVM calls MethodHandleNatives.<clinit>. Cascade the <clinit> calls as needed:
80 MethodHandleImpl.initStatics();
81 }
82
83 // All compile-time constants go here.
84 // There is an opportunity to check them against the JVM's idea of them.
85 static class Constants {
86 Constants() { } // static only
87 // MethodHandleImpl
88 static final int // for getConstant
89 GC_COUNT_GWT = 4,
90 GC_LAMBDA_SUPPORT = 5;
91
92 // MemberName
93 // The JVM uses values of -2 and above for vtable indexes.
94 // Field values are simple positive offsets.
95 // Ref: src/share/vm/oops/methodOop.hpp
96 // This value is negative enough to avoid such numbers,
97 // but not too negative.
98 static final int
99 MN_IS_METHOD = 0x00010000, // method (not constructor)
100 MN_IS_CONSTRUCTOR = 0x00020000, // constructor
101 MN_IS_FIELD = 0x00040000, // field
102 MN_IS_TYPE = 0x00080000, // nested type
103 MN_CALLER_SENSITIVE = 0x00100000, // @CallerSensitive annotation detected
104 MN_REFERENCE_KIND_SHIFT = 24, // refKind
105 MN_REFERENCE_KIND_MASK = 0x0F000000 >> MN_REFERENCE_KIND_SHIFT,
106 // The SEARCH_* bits are not for MN.flags but for the matchFlags argument of MHN.getMembers:
107 MN_SEARCH_SUPERCLASSES = 0x00100000,
108 MN_SEARCH_INTERFACES = 0x00200000;
109
110 /**
111 * Basic types as encoded in the JVM. These code values are not
112 * intended for use outside this class. They are used as part of
113 * a private interface between the JVM and this class.
114 */
115 static final int
116 T_BOOLEAN = 4,
117 T_CHAR = 5,
118 T_FLOAT = 6,
119 T_DOUBLE = 7,
120 T_BYTE = 8,
121 T_SHORT = 9,
122 T_INT = 10,
123 T_LONG = 11,
124 T_OBJECT = 12,
125 //T_ARRAY = 13
126 T_VOID = 14,
127 //T_ADDRESS = 15
128 T_ILLEGAL = 99;
129
130 /**
131 * Constant pool entry types.
132 */
133 static final byte
134 CONSTANT_Utf8 = 1,
135 CONSTANT_Integer = 3,
136 CONSTANT_Float = 4,
137 CONSTANT_Long = 5,
138 CONSTANT_Double = 6,
139 CONSTANT_Class = 7,
140 CONSTANT_String = 8,
141 CONSTANT_Fieldref = 9,
142 CONSTANT_Methodref = 10,
143 CONSTANT_InterfaceMethodref = 11,
144 CONSTANT_NameAndType = 12,
145 CONSTANT_MethodHandle = 15, // JSR 292
146 CONSTANT_MethodType = 16, // JSR 292
147 CONSTANT_InvokeDynamic = 18,
148 CONSTANT_LIMIT = 19; // Limit to tags found in classfiles
149
150 /**
151 * Access modifier flags.
152 */
153 static final char
154 ACC_PUBLIC = 0x0001,
155 ACC_PRIVATE = 0x0002,
156 ACC_PROTECTED = 0x0004,
157 ACC_STATIC = 0x0008,
158 ACC_FINAL = 0x0010,
159 ACC_SYNCHRONIZED = 0x0020,
160 ACC_VOLATILE = 0x0040,
161 ACC_TRANSIENT = 0x0080,
162 ACC_NATIVE = 0x0100,
163 ACC_INTERFACE = 0x0200,
164 ACC_ABSTRACT = 0x0400,
165 ACC_STRICT = 0x0800,
166 ACC_SYNTHETIC = 0x1000,
167 ACC_ANNOTATION = 0x2000,
168 ACC_ENUM = 0x4000,
169 // aliases:
170 ACC_SUPER = ACC_SYNCHRONIZED,
171 ACC_BRIDGE = ACC_VOLATILE,
172 ACC_VARARGS = ACC_TRANSIENT;
173
174 /**
175 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries.
176 */
177 static final byte
178 REF_NONE = 0, // null value
179 REF_getField = 1,
180 REF_getStatic = 2,
181 REF_putField = 3,
182 REF_putStatic = 4,
183 REF_invokeVirtual = 5,
184 REF_invokeStatic = 6,
185 REF_invokeSpecial = 7,
186 REF_newInvokeSpecial = 8,
187 REF_invokeInterface = 9,
188 REF_LIMIT = 10;
189 }
190
191 static boolean refKindIsValid(int refKind) {
192 return (refKind > REF_NONE && refKind < REF_LIMIT);
193 }
194 static boolean refKindIsField(byte refKind) {
195 assert(refKindIsValid(refKind));
196 return (refKind <= REF_putStatic);
197 }
198 static boolean refKindIsGetter(byte refKind) {
199 assert(refKindIsValid(refKind));
200 return (refKind <= REF_getStatic);
201 }
202 static boolean refKindIsSetter(byte refKind) {
203 return refKindIsField(refKind) && !refKindIsGetter(refKind);
204 }
205 static boolean refKindIsMethod(byte refKind) {
206 return !refKindIsField(refKind) && (refKind != REF_newInvokeSpecial);
207 }
208 static boolean refKindHasReceiver(byte refKind) {
209 assert(refKindIsValid(refKind));
210 return (refKind & 1) != 0;
211 }
212 static boolean refKindIsStatic(byte refKind) {
213 return !refKindHasReceiver(refKind) && (refKind != REF_newInvokeSpecial);
214 }
215 static boolean refKindDoesDispatch(byte refKind) {
216 assert(refKindIsValid(refKind));
217 return (refKind == REF_invokeVirtual ||
218 refKind == REF_invokeInterface);
219 }
220 static {
221 final int HR_MASK = ((1 << REF_getField) |
222 (1 << REF_putField) |
223 (1 << REF_invokeVirtual) |
224 (1 << REF_invokeSpecial) |
225 (1 << REF_invokeInterface)
226 );
227 for (byte refKind = REF_NONE+1; refKind < REF_LIMIT; refKind++) {
228 assert(refKindHasReceiver(refKind) == (((1<<refKind) & HR_MASK) != 0)) : refKind;
229 }
230 }
231 static String refKindName(byte refKind) {
232 assert(refKindIsValid(refKind));
233 return REFERENCE_KIND_NAME[refKind];
234 }
235 private static String[] REFERENCE_KIND_NAME = {
236 null,
237 "getField",
238 "getStatic",
239 "putField",
240 "putStatic",
241 "invokeVirtual",
242 "invokeStatic",
243 "invokeSpecial",
244 "newInvokeSpecial",
245 "invokeInterface"
246 };
247
248 private static native int getNamedCon(int which, Object[] name);
249 static boolean verifyConstants() {
250 Object[] box = { null };
251 for (int i = 0; ; i++) {
252 box[0] = null;
253 int vmval = getNamedCon(i, box);
254 if (box[0] == null) break;
255 String name = (String) box[0];
256 try {
257 Field con = Constants.class.getDeclaredField(name);
258 int jval = con.getInt(null);
259 if (jval == vmval) continue;
260 String err = (name+": JVM has "+vmval+" while Java has "+jval);
261 if (name.equals("CONV_OP_LIMIT")) {
262 System.err.println("warning: "+err);
263 continue;
264 }
265 throw new InternalError(err);
266 } catch (NoSuchFieldException | IllegalAccessException ex) {
267 String err = (name+": JVM has "+vmval+" which Java does not define");
268 // ignore exotic ops the JVM cares about; we just wont issue them
269 //System.err.println("warning: "+err);
270 continue;
271 }
272 }
273 return true;
274 }
275 static {
276 assert(verifyConstants());
277 }
278
279 // Up-calls from the JVM.
280 // These must NOT be public.
281
282 /**
283 * The JVM is linking an invokedynamic instruction. Create a reified call site for it.
284 */
285 static MemberName linkCallSite(Object callerObj,
286 Object bootstrapMethodObj,
287 Object nameObj, Object typeObj,
288 Object staticArguments,
289 Object[] appendixResult) {
290 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
291 Class<?> caller = (Class<?>)callerObj;
292 String name = nameObj.toString().intern();
293 MethodType type = (MethodType)typeObj;
294 appendixResult[0] = CallSite.makeSite(bootstrapMethod,
295 name,
296 type,
297 staticArguments,
298 caller);
299 return Invokers.linkToCallSiteMethod(type);
300 }
301
302 /**
303 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one.
304 */
305 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) {
306 return MethodType.makeImpl(rtype, ptypes, true);
307 }
308
309 /**
310 * The JVM wants to link a call site that requires a dynamic type check.
311 * Name is a type-checking invoker, invokeExact or invoke.
312 * Return a JVM method (MemberName) to handle the invoking.
313 * The method assumes the following arguments on the stack:
314 * 0: the method handle being invoked
315 * 1-N: the arguments to the method handle invocation
316 * N+1: an implicitly added type argument (the given MethodType)
317 */
318 static MemberName linkMethod(Class<?> callerClass, int refKind,
319 Class<?> defc, String name, Object type,
320 Object[] appendixResult) {
321 if (!TRACE_METHOD_LINKAGE)
322 return linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
323 return linkMethodTracing(callerClass, refKind, defc, name, type, appendixResult);
324 }
325 static MemberName linkMethodImpl(Class<?> callerClass, int refKind,
326 Class<?> defc, String name, Object type,
327 Object[] appendixResult) {
328 try {
329 if (defc == MethodHandle.class && refKind == REF_invokeVirtual) {
330 switch (name) {
331 case "invoke":
332 return Invokers.genericInvokerMethod(fixMethodType(callerClass, type), appendixResult);
333 case "invokeExact":
334 return Invokers.exactInvokerMethod(fixMethodType(callerClass, type), appendixResult);
335 }
336 }
337 } catch (Throwable ex) {
338 if (ex instanceof LinkageError)
339 throw (LinkageError) ex;
340 else
341 throw new LinkageError(ex.getMessage(), ex);
342 }
343 throw new LinkageError("no such method "+defc.getName()+"."+name+type);
344 }
345 private static MethodType fixMethodType(Class<?> callerClass, Object type) {
346 if (type instanceof MethodType)
347 return (MethodType) type;
348 else
349 return MethodType.fromMethodDescriptorString((String)type, callerClass.getClassLoader());
350 }
351 // Tracing logic:
352 static MemberName linkMethodTracing(Class<?> callerClass, int refKind,
353 Class<?> defc, String name, Object type,
354 Object[] appendixResult) {
355 System.out.println("linkMethod "+defc.getName()+"."+
356 name+type+"/"+Integer.toHexString(refKind));
357 try {
358 MemberName res = linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
359 System.out.println("linkMethod => "+res+" + "+appendixResult[0]);
360 return res;
361 } catch (Throwable ex) {
362 System.out.println("linkMethod => throw "+ex);
363 throw ex;
364 }
365 }
366
367
368 /**
369 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help.
370 * It will make an up-call to this method. (Do not change the name or signature.)
371 * The type argument is a Class for field requests and a MethodType for non-fields.
372 * <p>
373 * Recent versions of the JVM may also pass a resolved MemberName for the type.
374 * In that case, the name is ignored and may be null.
375 */
376 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
377 Class<?> defc, String name, Object type) {
378 try {
379 Lookup lookup = IMPL_LOOKUP.in(callerClass);
380 assert(refKindIsValid(refKind));
381 return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type);
382 } catch (IllegalAccessException ex) {
383 Error err = new IllegalAccessError(ex.getMessage());
384 // err.initCause(ex);
385 throw err;
386 } catch (ReflectiveOperationException ex) {
387 Error err = new IncompatibleClassChangeError();
388 err.initCause(ex);
389 throw err;
390 }
391 }
392
393 /**
394 * Is this method a caller-sensitive method?
395 * I.e., does it call Reflection.getCallerClass or a similer method
396 * to ask about the identity of its caller?
397 */
398 static boolean isCallerSensitive(MemberName mem) {
399 if (!mem.isInvocable()) return false; // fields are not caller sensitive
400
401 return mem.isCallerSensitive() || canBeCalledVirtual(mem);
402 }
403
404 static boolean canBeCalledVirtual(MemberName mem) {
405 assert(mem.isInvocable());
406 Class<?> defc = mem.getDeclaringClass();
407 switch (mem.getName()) {
408 case "checkMemberAccess":
409 return canBeCalledVirtual(mem, java.lang.SecurityManager.class);
410 case "getContextClassLoader":
411 return canBeCalledVirtual(mem, java.lang.Thread.class);
412 }
413 return false;
414 }
415
416 static boolean canBeCalledVirtual(MemberName symbolicRef, Class<?> definingClass) {
417 Class<?> symbolicRefClass = symbolicRef.getDeclaringClass();
418 if (symbolicRefClass == definingClass) return true;
419 if (symbolicRef.isStatic() || symbolicRef.isPrivate()) return false;
420 return (definingClass.isAssignableFrom(symbolicRefClass) || // Msym overrides Mdef
421 symbolicRefClass.isInterface()); // Mdef implements Msym
422 }
423 }