50 * @return the expected value, either a CallSite or a constant value
51 */
52 static <T> T invoke(Class<T> resultType,
53 MethodHandle bootstrapMethod,
54 // Callee information:
55 String name, Object type,
56 // Extra arguments for BSM, if any:
57 Object info,
58 // Caller information:
59 Class<?> callerClass) {
60 MethodHandles.Lookup caller = IMPL_LOOKUP.in(callerClass);
61 Object result;
62 boolean pullMode = isPullModeBSM(bootstrapMethod); // default value is false
63 boolean vmIsPushing = !staticArgumentsPulled(info); // default value is true
64 MethodHandle pullModeBSM;
65 // match the VM with the BSM
66 if (vmIsPushing) {
67 // VM is pushing arguments at us
68 pullModeBSM = null;
69 if (pullMode) {
70 bootstrapMethod = Adapters.pushMePullYou(bootstrapMethod, true);
71 }
72 } else {
73 // VM wants us to pull args from it
74 pullModeBSM = pullMode ? bootstrapMethod :
75 Adapters.pushMePullYou(bootstrapMethod, false);
76 bootstrapMethod = null;
77 }
78 try {
79 info = maybeReBox(info);
80 if (info == null) {
81 // VM is allowed to pass up a null meaning no BSM args
82 result = bootstrapMethod.invoke(caller, name, type);
83 }
84 else if (!info.getClass().isArray()) {
85 // VM is allowed to pass up a single BSM arg directly
86 result = bootstrapMethod.invoke(caller, name, type, info);
87 }
88 else if (info.getClass() == int[].class) {
89 // VM is allowed to pass up a pair {argc, index}
90 // referring to 'argc' BSM args at some place 'index'
91 // in the guts of the VM (associated with callerClass).
92 // The format of this index pair is private to the
93 // handshake between the VM and this class only.
94 // This supports "pulling" of arguments.
95 // The VM is allowed to do this for any reason.
220 Object res = wrapNull(buf[0]);
221 cache[i] = res;
222 int next = i + 1;
223 if (next < cache.length && cache[next] == null)
224 maybePrefetchIntoCache(next, false); // try to prefetch
225 return res;
226 }
227
228 @Override public int copyConstants(int start, int end,
229 Object[] buf, int pos) {
230 int i = start, bufi = pos;
231 while (i < end) {
232 Object x = cache[i];
233 if (x == null) break;
234 buf[bufi++] = unwrapNull(x);
235 i++;
236 }
237 // give up at first null and grab the rest in one big block
238 if (i >= end) return i;
239 Object[] temp = new Object[end - i];
240 if (TRACE_METHOD_LINKAGE)
241 System.out.println("resolving more BSM arguments: "+
242 Arrays.asList(caller.getSimpleName(), Arrays.toString(indexInfo), i, end));
243 copyOutBootstrapArguments(caller, indexInfo,
244 i, end, temp, 0,
245 true, null);
246 for (Object x : temp) {
247 x = maybeReBox(x);
248 buf[bufi++] = x;
249 cache[i++] = wrapNull(x);
250 }
251 if (end < cache.length && cache[end] == null)
252 maybePrefetchIntoCache(end, true); // try to prefetch
253 return i;
254 }
255
256 private static final int MIN_PF = 4;
257 private void maybePrefetchIntoCache(int i, boolean bulk) {
258 int len = cache.length;
259 assert(0 <= i && i <= len);
260 int pfLimit = i;
261 if (bulk) pfLimit += i; // exponential prefetch expansion
262 // try to prefetch at least MIN_PF elements
268 if (cache[j] == null) {
269 empty++;
270 lastEmpty = j;
271 } else {
272 nonEmpty++;
273 if (nonEmpty > empty) {
274 pfLimit = lastEmpty + 1;
275 break;
276 }
277 if (pfLimit < len) pfLimit++;
278 }
279 }
280 if (bulk && empty < MIN_PF && pfLimit < len)
281 return; // not worth the effort
282 prefetchIntoCache(i, pfLimit);
283 }
284
285 private void prefetchIntoCache(int i, int pfLimit) {
286 if (pfLimit <= i) return; // corner case
287 Object[] temp = new Object[pfLimit - i];
288 if (TRACE_METHOD_LINKAGE)
289 System.out.println("prefetching BSM arguments: "+
290 Arrays.asList(caller.getSimpleName(), Arrays.toString(indexInfo), i, pfLimit));
291 copyOutBootstrapArguments(caller, indexInfo,
292 i, pfLimit, temp, 0,
293 false, NOT_PRESENT);
294 for (Object x : temp) {
295 if (x != NOT_PRESENT && cache[i] == null) {
296 cache[i] = wrapNull(maybeReBox(x));
297 }
298 i++;
299 }
300 }
301 }
302
303 /*non-public*/ static final
304 class Adapters {
305 // skeleton for push-mode BSM which wraps a pull-mode BSM:
306 static Object pushToBootstrapMethod(MethodHandle pullModeBSM,
307 MethodHandles.Lookup lookup, String name, Object type,
308 Object... arguments) throws Throwable {
309 ConstantGroup cons = makeConstantGroup(Arrays.asList(arguments));
310 BootstrapCallInfo<?> bsci = makeBootstrapCallInfo(pullModeBSM, name, type, cons);
311 if (TRACE_METHOD_LINKAGE)
312 System.out.println("pull-mode BSM gets pushed arguments from fake BSCI");
313 return pullModeBSM.invoke(lookup, bsci);
314 }
315
316 // skeleton for pull-mode BSM which wraps a push-mode BSM:
317 static Object pullFromBootstrapMethod(MethodHandle pushModeBSM,
318 MethodHandles.Lookup lookup, BootstrapCallInfo<?> bsci)
319 throws Throwable {
320 int argc = bsci.size();
321 Object arguments[] = new Object[3 + argc];
322 arguments[0] = lookup;
323 arguments[1] = bsci.invocationName();
324 arguments[2] = bsci.invocationType();
325 bsci.copyConstants(0, argc, arguments, 3);
326 if (TRACE_METHOD_LINKAGE)
327 System.out.println("pulled arguments from VM for push-mode BSM");
328 return pushModeBSM.invokeWithArguments(arguments);
329 }
330 static final MethodHandle MH_pushToBootstrapMethod;
331 static final MethodHandle MH_pullFromBootstrapMethod;
332 static {
333 final Class<?> THIS_CLASS = Adapters.class;
334 try {
335 MH_pushToBootstrapMethod = IMPL_LOOKUP
336 .findStatic(THIS_CLASS, "pushToBootstrapMethod",
337 MethodType.methodType(Object.class, MethodHandle.class,
338 Lookup.class, String.class, Object.class, Object[].class));
339 MH_pullFromBootstrapMethod = IMPL_LOOKUP
340 .findStatic(THIS_CLASS, "pullFromBootstrapMethod",
341 MethodType.methodType(Object.class, MethodHandle.class,
342 Lookup.class, BootstrapCallInfo.class));
343 } catch (Throwable ex) {
344 throw new InternalError(ex);
345 }
346 }
347
348 /** Given a push-mode BSM (taking one argument) convert it to a
349 * pull-mode BSM (taking N pre-resolved arguments).
350 * This method is used when, in fact, the JVM is passing up
351 * pre-resolved arguments, but the BSM is expecting lazy stuff.
352 * Or, when goToPushMode is true, do the reverse transform.
353 * (The two transforms are exactly inverse.)
354 */
355 static MethodHandle pushMePullYou(MethodHandle bsm, boolean goToPushMode) {
356 if (TRACE_METHOD_LINKAGE)
357 System.out.println("converting BSM to "+(goToPushMode ? "push mode" : "pull mode"));
358 assert(isPullModeBSM(bsm) == goToPushMode); //there must be a change
359 if (goToPushMode) {
360 return Adapters.MH_pushToBootstrapMethod.bindTo(bsm).withVarargs(true);
361 } else {
362 return Adapters.MH_pullFromBootstrapMethod.bindTo(bsm).withVarargs(false);
363 }
364 }
365 }
366 }
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50 * @return the expected value, either a CallSite or a constant value
51 */
52 static <T> T invoke(Class<T> resultType,
53 MethodHandle bootstrapMethod,
54 // Callee information:
55 String name, Object type,
56 // Extra arguments for BSM, if any:
57 Object info,
58 // Caller information:
59 Class<?> callerClass) {
60 MethodHandles.Lookup caller = IMPL_LOOKUP.in(callerClass);
61 Object result;
62 boolean pullMode = isPullModeBSM(bootstrapMethod); // default value is false
63 boolean vmIsPushing = !staticArgumentsPulled(info); // default value is true
64 MethodHandle pullModeBSM;
65 // match the VM with the BSM
66 if (vmIsPushing) {
67 // VM is pushing arguments at us
68 pullModeBSM = null;
69 if (pullMode) {
70 bootstrapMethod = pushMePullYou(bootstrapMethod, true);
71 }
72 } else {
73 // VM wants us to pull args from it
74 pullModeBSM = pullMode ? bootstrapMethod :
75 pushMePullYou(bootstrapMethod, false);
76 bootstrapMethod = null;
77 }
78 try {
79 info = maybeReBox(info);
80 if (info == null) {
81 // VM is allowed to pass up a null meaning no BSM args
82 result = bootstrapMethod.invoke(caller, name, type);
83 }
84 else if (!info.getClass().isArray()) {
85 // VM is allowed to pass up a single BSM arg directly
86 result = bootstrapMethod.invoke(caller, name, type, info);
87 }
88 else if (info.getClass() == int[].class) {
89 // VM is allowed to pass up a pair {argc, index}
90 // referring to 'argc' BSM args at some place 'index'
91 // in the guts of the VM (associated with callerClass).
92 // The format of this index pair is private to the
93 // handshake between the VM and this class only.
94 // This supports "pulling" of arguments.
95 // The VM is allowed to do this for any reason.
220 Object res = wrapNull(buf[0]);
221 cache[i] = res;
222 int next = i + 1;
223 if (next < cache.length && cache[next] == null)
224 maybePrefetchIntoCache(next, false); // try to prefetch
225 return res;
226 }
227
228 @Override public int copyConstants(int start, int end,
229 Object[] buf, int pos) {
230 int i = start, bufi = pos;
231 while (i < end) {
232 Object x = cache[i];
233 if (x == null) break;
234 buf[bufi++] = unwrapNull(x);
235 i++;
236 }
237 // give up at first null and grab the rest in one big block
238 if (i >= end) return i;
239 Object[] temp = new Object[end - i];
240 if (TRACE_METHOD_LINKAGE) {
241 System.out.println("resolving more BSM arguments: " +
242 Arrays.asList(caller.getSimpleName(), Arrays.toString(indexInfo), i, end));
243 }
244 copyOutBootstrapArguments(caller, indexInfo,
245 i, end, temp, 0,
246 true, null);
247 for (Object x : temp) {
248 x = maybeReBox(x);
249 buf[bufi++] = x;
250 cache[i++] = wrapNull(x);
251 }
252 if (end < cache.length && cache[end] == null)
253 maybePrefetchIntoCache(end, true); // try to prefetch
254 return i;
255 }
256
257 private static final int MIN_PF = 4;
258 private void maybePrefetchIntoCache(int i, boolean bulk) {
259 int len = cache.length;
260 assert(0 <= i && i <= len);
261 int pfLimit = i;
262 if (bulk) pfLimit += i; // exponential prefetch expansion
263 // try to prefetch at least MIN_PF elements
269 if (cache[j] == null) {
270 empty++;
271 lastEmpty = j;
272 } else {
273 nonEmpty++;
274 if (nonEmpty > empty) {
275 pfLimit = lastEmpty + 1;
276 break;
277 }
278 if (pfLimit < len) pfLimit++;
279 }
280 }
281 if (bulk && empty < MIN_PF && pfLimit < len)
282 return; // not worth the effort
283 prefetchIntoCache(i, pfLimit);
284 }
285
286 private void prefetchIntoCache(int i, int pfLimit) {
287 if (pfLimit <= i) return; // corner case
288 Object[] temp = new Object[pfLimit - i];
289 if (TRACE_METHOD_LINKAGE) {
290 System.out.println("prefetching BSM arguments: " +
291 Arrays.asList(caller.getSimpleName(), Arrays.toString(indexInfo), i, pfLimit));
292 }
293 copyOutBootstrapArguments(caller, indexInfo,
294 i, pfLimit, temp, 0,
295 false, NOT_PRESENT);
296 for (Object x : temp) {
297 if (x != NOT_PRESENT && cache[i] == null) {
298 cache[i] = wrapNull(maybeReBox(x));
299 }
300 i++;
301 }
302 }
303 }
304
305 /*non-public*/ static final
306 class PushAdapter {
307 // skeleton for push-mode BSM which wraps a pull-mode BSM:
308 static Object pushToBootstrapMethod(MethodHandle pullModeBSM,
309 MethodHandles.Lookup lookup, String name, Object type,
310 Object... arguments) throws Throwable {
311 ConstantGroup cons = makeConstantGroup(Arrays.asList(arguments));
312 BootstrapCallInfo<?> bsci = makeBootstrapCallInfo(pullModeBSM, name, type, cons);
313 if (TRACE_METHOD_LINKAGE)
314 System.out.println("pull-mode BSM gets pushed arguments from fake BSCI");
315 return pullModeBSM.invoke(lookup, bsci);
316 }
317
318 static final MethodHandle MH_pushToBootstrapMethod;
319 static {
320 final Class<?> THIS_CLASS = PushAdapter.class;
321 try {
322 MH_pushToBootstrapMethod = IMPL_LOOKUP
323 .findStatic(THIS_CLASS, "pushToBootstrapMethod",
324 MethodType.methodType(Object.class, MethodHandle.class,
325 Lookup.class, String.class, Object.class, Object[].class));
326 } catch (Throwable ex) {
327 throw new InternalError(ex);
328 }
329 }
330 }
331
332 /*non-public*/ static final
333 class PullAdapter {
334 // skeleton for pull-mode BSM which wraps a push-mode BSM:
335 static Object pullFromBootstrapMethod(MethodHandle pushModeBSM,
336 MethodHandles.Lookup lookup,
337 BootstrapCallInfo<?> bsci)
338 throws Throwable {
339 int argc = bsci.size();
340 switch (argc) {
341 case 0:
342 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType());
343 case 1:
344 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
345 bsci.get(0));
346 case 2:
347 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
348 bsci.get(0), bsci.get(1));
349 case 3:
350 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
351 bsci.get(0), bsci.get(1), bsci.get(2));
352 case 4:
353 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
354 bsci.get(0), bsci.get(1), bsci.get(2), bsci.get(3));
355 case 5:
356 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
357 bsci.get(0), bsci.get(1), bsci.get(2), bsci.get(3), bsci.get(4));
358 case 6:
359 return pushModeBSM.invoke(lookup, bsci.invocationName(), bsci.invocationType(),
360 bsci.get(0), bsci.get(1), bsci.get(2), bsci.get(3), bsci.get(4), bsci.get(5));
361 default:
362 final int NON_SPREAD_ARG_COUNT = 3; // (lookup, name, type)
363 final int MAX_SAFE_SIZE = MethodType.MAX_MH_ARITY / 2 - NON_SPREAD_ARG_COUNT;
364 if (argc >= MAX_SAFE_SIZE) {
365 // to be on the safe side, use invokeWithArguments which handles jumbo lists
366 Object[] newargv = new Object[NON_SPREAD_ARG_COUNT + argc];
367 newargv[0] = lookup;
368 newargv[1] = bsci.invocationName();
369 newargv[2] = bsci.invocationType();
370 bsci.copyConstants(0, argc, newargv, NON_SPREAD_ARG_COUNT);
371 return pushModeBSM.invokeWithArguments(newargv);
372 }
373 MethodType invocationType = MethodType.genericMethodType(NON_SPREAD_ARG_COUNT + argc);
374 MethodHandle typedBSM = pushModeBSM.asType(invocationType);
375 MethodHandle spreader = invocationType.invokers().spreadInvoker(NON_SPREAD_ARG_COUNT);
376 Object[] argv = new Object[argc];
377 bsci.copyConstants(0, argc, argv, 0);
378 return spreader.invokeExact(typedBSM, (Object) lookup, (Object) bsci.invocationName(), bsci.invocationType(), argv);
379 }
380 }
381
382 static final MethodHandle MH_pullFromBootstrapMethod;
383
384 static {
385 final Class<?> THIS_CLASS = PullAdapter.class;
386 try {
387 MH_pullFromBootstrapMethod = IMPL_LOOKUP
388 .findStatic(THIS_CLASS, "pullFromBootstrapMethod",
389 MethodType.methodType(Object.class, MethodHandle.class,
390 Lookup.class, BootstrapCallInfo.class));
391 } catch (Throwable ex) {
392 throw new InternalError(ex);
393 }
394 }
395 }
396
397 /** Given a push-mode BSM (taking one argument) convert it to a
398 * pull-mode BSM (taking N pre-resolved arguments).
399 * This method is used when, in fact, the JVM is passing up
400 * pre-resolved arguments, but the BSM is expecting lazy stuff.
401 * Or, when goToPushMode is true, do the reverse transform.
402 * (The two transforms are exactly inverse.)
403 */
404 static MethodHandle pushMePullYou(MethodHandle bsm, boolean goToPushMode) {
405 if (TRACE_METHOD_LINKAGE) {
406 System.out.println("converting BSM of type " + bsm.type() + " to "
407 + (goToPushMode ? "push mode" : "pull mode"));
408 }
409 assert(isPullModeBSM(bsm) == goToPushMode); // there must be a change
410 if (goToPushMode) {
411 return PushAdapter.MH_pushToBootstrapMethod.bindTo(bsm).withVarargs(true);
412 } else {
413 return PullAdapter.MH_pullFromBootstrapMethod.bindTo(bsm).withVarargs(false);
414 }
415 }
416 }
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