1 /*
2 * Copyright (c) 1998, 2021, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "cds/metaspaceShared.hpp"
27 #include "classfile/vmClasses.hpp"
28 #include "interpreter/bytecodes.hpp"
29 #include "interpreter/interpreter.hpp"
30 #include "interpreter/rewriter.hpp"
31 #include "memory/metadataFactory.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/constantPool.hpp"
34 #include "oops/generateOopMap.hpp"
35 #include "prims/methodHandles.hpp"
36 #include "runtime/fieldDescriptor.inline.hpp"
37 #include "runtime/handles.inline.hpp"
38
39 // Computes a CPC map (new_index -> original_index) for constant pool entries
40 // that are referred to by the interpreter at runtime via the constant pool cache.
41 // Also computes a CP map (original_index -> new_index).
42 // Marks entries in CP which require additional processing.
compute_index_maps()43 void Rewriter::compute_index_maps() {
44 const int length = _pool->length();
45 init_maps(length);
46 bool saw_mh_symbol = false;
47 for (int i = 0; i < length; i++) {
48 int tag = _pool->tag_at(i).value();
49 switch (tag) {
50 case JVM_CONSTANT_InterfaceMethodref:
51 case JVM_CONSTANT_Fieldref : // fall through
52 case JVM_CONSTANT_Methodref : // fall through
53 add_cp_cache_entry(i);
54 break;
55 case JVM_CONSTANT_Dynamic:
56 assert(_pool->has_dynamic_constant(), "constant pool's _has_dynamic_constant flag not set");
57 add_resolved_references_entry(i);
58 break;
59 case JVM_CONSTANT_String : // fall through
60 case JVM_CONSTANT_MethodHandle : // fall through
61 case JVM_CONSTANT_MethodType : // fall through
62 add_resolved_references_entry(i);
63 break;
64 case JVM_CONSTANT_Utf8:
65 if (_pool->symbol_at(i) == vmSymbols::java_lang_invoke_MethodHandle() ||
66 _pool->symbol_at(i) == vmSymbols::java_lang_invoke_VarHandle()) {
67 saw_mh_symbol = true;
68 }
69 break;
70 }
71 }
72
73 // Record limits of resolved reference map for constant pool cache indices
74 record_map_limits();
75
76 guarantee((int) _cp_cache_map.length() - 1 <= (int) ((u2)-1),
77 "all cp cache indexes fit in a u2");
78
79 if (saw_mh_symbol) {
80 _method_handle_invokers.at_grow(length, 0);
81 }
82 }
83
84 // Unrewrite the bytecodes if an error occurs.
restore_bytecodes(Thread * thread)85 void Rewriter::restore_bytecodes(Thread* thread) {
86 int len = _methods->length();
87 bool invokespecial_error = false;
88
89 for (int i = len-1; i >= 0; i--) {
90 Method* method = _methods->at(i);
91 scan_method(thread, method, true, &invokespecial_error);
92 assert(!invokespecial_error, "reversing should not get an invokespecial error");
93 }
94 }
95
96 // Creates a constant pool cache given a CPC map
make_constant_pool_cache(TRAPS)97 void Rewriter::make_constant_pool_cache(TRAPS) {
98 ClassLoaderData* loader_data = _pool->pool_holder()->class_loader_data();
99 ConstantPoolCache* cache =
100 ConstantPoolCache::allocate(loader_data, _cp_cache_map,
101 _invokedynamic_cp_cache_map,
102 _invokedynamic_references_map, CHECK);
103
104 // initialize object cache in constant pool
105 _pool->set_cache(cache);
106 cache->set_constant_pool(_pool());
107
108 // _resolved_references is stored in pool->cache(), so need to be done after
109 // the above lines.
110 _pool->initialize_resolved_references(loader_data, _resolved_references_map,
111 _resolved_reference_limit,
112 THREAD);
113
114 // Clean up constant pool cache if initialize_resolved_references() failed.
115 if (HAS_PENDING_EXCEPTION) {
116 MetadataFactory::free_metadata(loader_data, cache);
117 _pool->set_cache(NULL); // so the verifier isn't confused
118 } else {
119 DEBUG_ONLY(
120 if (DumpSharedSpaces) {
121 cache->verify_just_initialized();
122 })
123 }
124 }
125
126
127
128 // The new finalization semantics says that registration of
129 // finalizable objects must be performed on successful return from the
130 // Object.<init> constructor. We could implement this trivially if
131 // <init> were never rewritten but since JVMTI allows this to occur, a
132 // more complicated solution is required. A special return bytecode
133 // is used only by Object.<init> to signal the finalization
134 // registration point. Additionally local 0 must be preserved so it's
135 // available to pass to the registration function. For simplicity we
136 // require that local 0 is never overwritten so it's available as an
137 // argument for registration.
138
rewrite_Object_init(const methodHandle & method,TRAPS)139 void Rewriter::rewrite_Object_init(const methodHandle& method, TRAPS) {
140 RawBytecodeStream bcs(method);
141 while (!bcs.is_last_bytecode()) {
142 Bytecodes::Code opcode = bcs.raw_next();
143 switch (opcode) {
144 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
145
146 case Bytecodes::_istore:
147 case Bytecodes::_lstore:
148 case Bytecodes::_fstore:
149 case Bytecodes::_dstore:
150 case Bytecodes::_astore:
151 if (bcs.get_index() != 0) continue;
152
153 // fall through
154 case Bytecodes::_istore_0:
155 case Bytecodes::_lstore_0:
156 case Bytecodes::_fstore_0:
157 case Bytecodes::_dstore_0:
158 case Bytecodes::_astore_0:
159 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
160 "can't overwrite local 0 in Object.<init>");
161 break;
162
163 default:
164 break;
165 }
166 }
167 }
168
169
170 // Rewrite a classfile-order CP index into a native-order CPC index.
rewrite_member_reference(address bcp,int offset,bool reverse)171 void Rewriter::rewrite_member_reference(address bcp, int offset, bool reverse) {
172 address p = bcp + offset;
173 if (!reverse) {
174 int cp_index = Bytes::get_Java_u2(p);
175 int cache_index = cp_entry_to_cp_cache(cp_index);
176 Bytes::put_native_u2(p, cache_index);
177 if (!_method_handle_invokers.is_empty())
178 maybe_rewrite_invokehandle(p - 1, cp_index, cache_index, reverse);
179 } else {
180 int cache_index = Bytes::get_native_u2(p);
181 int pool_index = cp_cache_entry_pool_index(cache_index);
182 Bytes::put_Java_u2(p, pool_index);
183 if (!_method_handle_invokers.is_empty())
184 maybe_rewrite_invokehandle(p - 1, pool_index, cache_index, reverse);
185 }
186 }
187
188 // If the constant pool entry for invokespecial is InterfaceMethodref,
189 // we need to add a separate cpCache entry for its resolution, because it is
190 // different than the resolution for invokeinterface with InterfaceMethodref.
191 // These cannot share cpCache entries.
rewrite_invokespecial(address bcp,int offset,bool reverse,bool * invokespecial_error)192 void Rewriter::rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error) {
193 address p = bcp + offset;
194 if (!reverse) {
195 int cp_index = Bytes::get_Java_u2(p);
196 if (_pool->tag_at(cp_index).is_interface_method()) {
197 int cache_index = add_invokespecial_cp_cache_entry(cp_index);
198 if (cache_index != (int)(jushort) cache_index) {
199 *invokespecial_error = true;
200 }
201 Bytes::put_native_u2(p, cache_index);
202 } else {
203 rewrite_member_reference(bcp, offset, reverse);
204 }
205 } else {
206 rewrite_member_reference(bcp, offset, reverse);
207 }
208 }
209
210
211 // Adjust the invocation bytecode for a signature-polymorphic method (MethodHandle.invoke, etc.)
maybe_rewrite_invokehandle(address opc,int cp_index,int cache_index,bool reverse)212 void Rewriter::maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse) {
213 if (!reverse) {
214 if ((*opc) == (u1)Bytecodes::_invokevirtual ||
215 // allow invokespecial as an alias, although it would be very odd:
216 (*opc) == (u1)Bytecodes::_invokespecial) {
217 assert(_pool->tag_at(cp_index).is_method(), "wrong index");
218 // Determine whether this is a signature-polymorphic method.
219 if (cp_index >= _method_handle_invokers.length()) return;
220 int status = _method_handle_invokers.at(cp_index);
221 assert(status >= -1 && status <= 1, "oob tri-state");
222 if (status == 0) {
223 if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_MethodHandle() &&
224 MethodHandles::is_signature_polymorphic_name(vmClasses::MethodHandle_klass(),
225 _pool->name_ref_at(cp_index))) {
226 // we may need a resolved_refs entry for the appendix
227 add_invokedynamic_resolved_references_entry(cp_index, cache_index);
228 status = +1;
229 } else if (_pool->klass_ref_at_noresolve(cp_index) == vmSymbols::java_lang_invoke_VarHandle() &&
230 MethodHandles::is_signature_polymorphic_name(vmClasses::VarHandle_klass(),
231 _pool->name_ref_at(cp_index))) {
232 // we may need a resolved_refs entry for the appendix
233 add_invokedynamic_resolved_references_entry(cp_index, cache_index);
234 status = +1;
235 } else {
236 status = -1;
237 }
238 _method_handle_invokers.at(cp_index) = status;
239 }
240 // We use a special internal bytecode for such methods (if non-static).
241 // The basic reason for this is that such methods need an extra "appendix" argument
242 // to transmit the call site's intended call type.
243 if (status > 0) {
244 (*opc) = (u1)Bytecodes::_invokehandle;
245 }
246 }
247 } else {
248 // Do not need to look at cp_index.
249 if ((*opc) == (u1)Bytecodes::_invokehandle) {
250 (*opc) = (u1)Bytecodes::_invokevirtual;
251 // Ignore corner case of original _invokespecial instruction.
252 // This is safe because (a) the signature polymorphic method was final, and
253 // (b) the implementation of MethodHandle will not call invokespecial on it.
254 }
255 }
256 }
257
258
rewrite_invokedynamic(address bcp,int offset,bool reverse)259 void Rewriter::rewrite_invokedynamic(address bcp, int offset, bool reverse) {
260 address p = bcp + offset;
261 assert(p[-1] == Bytecodes::_invokedynamic, "not invokedynamic bytecode");
262 if (!reverse) {
263 int cp_index = Bytes::get_Java_u2(p);
264 int cache_index = add_invokedynamic_cp_cache_entry(cp_index);
265 int resolved_index = add_invokedynamic_resolved_references_entry(cp_index, cache_index);
266 // Replace the trailing four bytes with a CPC index for the dynamic
267 // call site. Unlike other CPC entries, there is one per bytecode,
268 // not just one per distinct CP entry. In other words, the
269 // CPC-to-CP relation is many-to-one for invokedynamic entries.
270 // This means we must use a larger index size than u2 to address
271 // all these entries. That is the main reason invokedynamic
272 // must have a five-byte instruction format. (Of course, other JVM
273 // implementations can use the bytes for other purposes.)
274 // Note: We use native_u4 format exclusively for 4-byte indexes.
275 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index));
276 // add the bcp in case we need to patch this bytecode if we also find a
277 // invokespecial/InterfaceMethodref in the bytecode stream
278 _patch_invokedynamic_bcps->push(p);
279 _patch_invokedynamic_refs->push(resolved_index);
280 } else {
281 int cache_index = ConstantPool::decode_invokedynamic_index(
282 Bytes::get_native_u4(p));
283 // We will reverse the bytecode rewriting _after_ adjusting them.
284 // Adjust the cache index by offset to the invokedynamic entries in the
285 // cpCache plus the delta if the invokedynamic bytecodes were adjusted.
286 int adjustment = cp_cache_delta() + _first_iteration_cp_cache_limit;
287 int cp_index = invokedynamic_cp_cache_entry_pool_index(cache_index - adjustment);
288 assert(_pool->tag_at(cp_index).is_invoke_dynamic(), "wrong index");
289 // zero out 4 bytes
290 Bytes::put_Java_u4(p, 0);
291 Bytes::put_Java_u2(p, cp_index);
292 }
293 }
294
patch_invokedynamic_bytecodes()295 void Rewriter::patch_invokedynamic_bytecodes() {
296 // If the end of the cp_cache is the same as after initializing with the
297 // cpool, nothing needs to be done. Invokedynamic bytecodes are at the
298 // correct offsets. ie. no invokespecials added
299 int delta = cp_cache_delta();
300 if (delta > 0) {
301 int length = _patch_invokedynamic_bcps->length();
302 assert(length == _patch_invokedynamic_refs->length(),
303 "lengths should match");
304 for (int i = 0; i < length; i++) {
305 address p = _patch_invokedynamic_bcps->at(i);
306 int cache_index = ConstantPool::decode_invokedynamic_index(
307 Bytes::get_native_u4(p));
308 Bytes::put_native_u4(p, ConstantPool::encode_invokedynamic_index(cache_index + delta));
309
310 // invokedynamic resolved references map also points to cp cache and must
311 // add delta to each.
312 int resolved_index = _patch_invokedynamic_refs->at(i);
313 assert(_invokedynamic_references_map.at(resolved_index) == cache_index,
314 "should be the same index");
315 _invokedynamic_references_map.at_put(resolved_index, cache_index + delta);
316 }
317 }
318 }
319
320
321 // Rewrite some ldc bytecodes to _fast_aldc
maybe_rewrite_ldc(address bcp,int offset,bool is_wide,bool reverse)322 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide,
323 bool reverse) {
324 if (!reverse) {
325 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "not ldc bytecode");
326 address p = bcp + offset;
327 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
328 constantTag tag = _pool->tag_at(cp_index).value();
329
330 if (tag.is_method_handle() ||
331 tag.is_method_type() ||
332 tag.is_string() ||
333 (tag.is_dynamic_constant() &&
334 // keep regular ldc interpreter logic for condy primitives
335 is_reference_type(Signature::basic_type(_pool->uncached_signature_ref_at(cp_index))))
336 ) {
337 int ref_index = cp_entry_to_resolved_references(cp_index);
338 if (is_wide) {
339 (*bcp) = Bytecodes::_fast_aldc_w;
340 assert(ref_index == (u2)ref_index, "index overflow");
341 Bytes::put_native_u2(p, ref_index);
342 } else {
343 (*bcp) = Bytecodes::_fast_aldc;
344 assert(ref_index == (u1)ref_index, "index overflow");
345 (*p) = (u1)ref_index;
346 }
347 }
348 } else {
349 Bytecodes::Code rewritten_bc =
350 (is_wide ? Bytecodes::_fast_aldc_w : Bytecodes::_fast_aldc);
351 if ((*bcp) == rewritten_bc) {
352 address p = bcp + offset;
353 int ref_index = is_wide ? Bytes::get_native_u2(p) : (u1)(*p);
354 int pool_index = resolved_references_entry_to_pool_index(ref_index);
355 if (is_wide) {
356 (*bcp) = Bytecodes::_ldc_w;
357 assert(pool_index == (u2)pool_index, "index overflow");
358 Bytes::put_Java_u2(p, pool_index);
359 } else {
360 (*bcp) = Bytecodes::_ldc;
361 assert(pool_index == (u1)pool_index, "index overflow");
362 (*p) = (u1)pool_index;
363 }
364 }
365 }
366 }
367
368
369 // Rewrites a method given the index_map information
scan_method(Thread * thread,Method * method,bool reverse,bool * invokespecial_error)370 void Rewriter::scan_method(Thread* thread, Method* method, bool reverse, bool* invokespecial_error) {
371
372 int nof_jsrs = 0;
373 bool has_monitor_bytecodes = false;
374 Bytecodes::Code c;
375
376 // Bytecodes and their length
377 const address code_base = method->code_base();
378 const int code_length = method->code_size();
379
380 int bc_length;
381 for (int bci = 0; bci < code_length; bci += bc_length) {
382 address bcp = code_base + bci;
383 int prefix_length = 0;
384 c = (Bytecodes::Code)(*bcp);
385
386 // Since we have the code, see if we can get the length
387 // directly. Some more complicated bytecodes will report
388 // a length of zero, meaning we need to make another method
389 // call to calculate the length.
390 bc_length = Bytecodes::length_for(c);
391 if (bc_length == 0) {
392 bc_length = Bytecodes::length_at(method, bcp);
393
394 // length_at will put us at the bytecode after the one modified
395 // by 'wide'. We don't currently examine any of the bytecodes
396 // modified by wide, but in case we do in the future...
397 if (c == Bytecodes::_wide) {
398 prefix_length = 1;
399 c = (Bytecodes::Code)bcp[1];
400 }
401 }
402
403 // Continuing with an invalid bytecode will fail in the loop below.
404 // So guarantee here.
405 guarantee(bc_length > 0, "Verifier should have caught this invalid bytecode");
406
407 switch (c) {
408 case Bytecodes::_lookupswitch : {
409 #ifndef ZERO
410 Bytecode_lookupswitch bc(method, bcp);
411 (*bcp) = (
412 bc.number_of_pairs() < BinarySwitchThreshold
413 ? Bytecodes::_fast_linearswitch
414 : Bytecodes::_fast_binaryswitch
415 );
416 #endif
417 break;
418 }
419 case Bytecodes::_fast_linearswitch:
420 case Bytecodes::_fast_binaryswitch: {
421 #ifndef ZERO
422 (*bcp) = Bytecodes::_lookupswitch;
423 #endif
424 break;
425 }
426
427 case Bytecodes::_invokespecial : {
428 rewrite_invokespecial(bcp, prefix_length+1, reverse, invokespecial_error);
429 break;
430 }
431
432 case Bytecodes::_putstatic :
433 case Bytecodes::_putfield : {
434 if (!reverse) {
435 // Check if any final field of the class given as parameter is modified
436 // outside of initializer methods of the class. Fields that are modified
437 // are marked with a flag. For marked fields, the compilers do not perform
438 // constant folding (as the field can be changed after initialization).
439 //
440 // The check is performed after verification and only if verification has
441 // succeeded. Therefore, the class is guaranteed to be well-formed.
442 InstanceKlass* klass = method->method_holder();
443 u2 bc_index = Bytes::get_Java_u2(bcp + prefix_length + 1);
444 constantPoolHandle cp(thread, method->constants());
445 Symbol* ref_class_name = cp->klass_name_at(cp->klass_ref_index_at(bc_index));
446
447 if (klass->name() == ref_class_name) {
448 Symbol* field_name = cp->name_ref_at(bc_index);
449 Symbol* field_sig = cp->signature_ref_at(bc_index);
450
451 fieldDescriptor fd;
452 if (klass->find_field(field_name, field_sig, &fd) != NULL) {
453 if (fd.access_flags().is_final()) {
454 if (fd.access_flags().is_static()) {
455 if (!method->is_static_initializer()) {
456 fd.set_has_initialized_final_update(true);
457 }
458 } else {
459 if (!method->is_object_initializer()) {
460 fd.set_has_initialized_final_update(true);
461 }
462 }
463 }
464 }
465 }
466 }
467 }
468 // fall through
469 case Bytecodes::_getstatic : // fall through
470 case Bytecodes::_getfield : // fall through
471 case Bytecodes::_invokevirtual : // fall through
472 case Bytecodes::_invokestatic :
473 case Bytecodes::_invokeinterface:
474 case Bytecodes::_invokehandle : // if reverse=true
475 rewrite_member_reference(bcp, prefix_length+1, reverse);
476 break;
477 case Bytecodes::_invokedynamic:
478 rewrite_invokedynamic(bcp, prefix_length+1, reverse);
479 break;
480 case Bytecodes::_ldc:
481 case Bytecodes::_fast_aldc: // if reverse=true
482 maybe_rewrite_ldc(bcp, prefix_length+1, false, reverse);
483 break;
484 case Bytecodes::_ldc_w:
485 case Bytecodes::_fast_aldc_w: // if reverse=true
486 maybe_rewrite_ldc(bcp, prefix_length+1, true, reverse);
487 break;
488 case Bytecodes::_jsr : // fall through
489 case Bytecodes::_jsr_w : nof_jsrs++; break;
490 case Bytecodes::_monitorenter : // fall through
491 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break;
492
493 default: break;
494 }
495 }
496
497 // Update access flags
498 if (has_monitor_bytecodes) {
499 method->set_has_monitor_bytecodes();
500 }
501
502 // The present of a jsr bytecode implies that the method might potentially
503 // have to be rewritten, so we run the oopMapGenerator on the method
504 if (nof_jsrs > 0) {
505 method->set_has_jsrs();
506 // Second pass will revisit this method.
507 assert(method->has_jsrs(), "didn't we just set this?");
508 }
509 }
510
511 // After constant pool is created, revisit methods containing jsrs.
rewrite_jsrs(const methodHandle & method,TRAPS)512 methodHandle Rewriter::rewrite_jsrs(const methodHandle& method, TRAPS) {
513 ResourceMark rm(THREAD);
514 ResolveOopMapConflicts romc(method);
515 methodHandle new_method = romc.do_potential_rewrite(CHECK_(methodHandle()));
516 // Update monitor matching info.
517 if (romc.monitor_safe()) {
518 new_method->set_guaranteed_monitor_matching();
519 }
520
521 return new_method;
522 }
523
rewrite_bytecodes(TRAPS)524 void Rewriter::rewrite_bytecodes(TRAPS) {
525 assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
526
527 // determine index maps for Method* rewriting
528 compute_index_maps();
529
530 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
531 bool did_rewrite = false;
532 int i = _methods->length();
533 while (i-- > 0) {
534 Method* method = _methods->at(i);
535 if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
536 // rewrite the return bytecodes of Object.<init> to register the
537 // object for finalization if needed.
538 methodHandle m(THREAD, method);
539 rewrite_Object_init(m, CHECK);
540 did_rewrite = true;
541 break;
542 }
543 }
544 assert(did_rewrite, "must find Object::<init> to rewrite it");
545 }
546
547 // rewrite methods, in two passes
548 int len = _methods->length();
549 bool invokespecial_error = false;
550
551 for (int i = len-1; i >= 0; i--) {
552 Method* method = _methods->at(i);
553 scan_method(THREAD, method, false, &invokespecial_error);
554 if (invokespecial_error) {
555 // If you get an error here, there is no reversing bytecodes
556 // This exception is stored for this class and no further attempt is
557 // made at verifying or rewriting.
558 THROW_MSG(vmSymbols::java_lang_InternalError(),
559 "This classfile overflows invokespecial for interfaces "
560 "and cannot be loaded");
561 return;
562 }
563 }
564
565 // May have to fix invokedynamic bytecodes if invokestatic/InterfaceMethodref
566 // entries had to be added.
567 patch_invokedynamic_bytecodes();
568 }
569
rewrite(InstanceKlass * klass,TRAPS)570 void Rewriter::rewrite(InstanceKlass* klass, TRAPS) {
571 #if INCLUDE_CDS
572 if (klass->is_shared()) {
573 assert(!klass->is_rewritten(), "rewritten shared classes cannot be rewritten again");
574 assert(!klass->can_be_verified_at_dumptime(), "only shared old classes aren't rewritten");
575 }
576 #endif // INCLUDE_CDS
577 ResourceMark rm(THREAD);
578 constantPoolHandle cpool(THREAD, klass->constants());
579 Rewriter rw(klass, cpool, klass->methods(), CHECK);
580 // (That's all, folks.)
581 }
582
Rewriter(InstanceKlass * klass,const constantPoolHandle & cpool,Array<Method * > * methods,TRAPS)583 Rewriter::Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS)
584 : _klass(klass),
585 _pool(cpool),
586 _methods(methods),
587 _cp_map(cpool->length()),
588 _cp_cache_map(cpool->length() / 2),
589 _reference_map(cpool->length()),
590 _resolved_references_map(cpool->length() / 2),
591 _invokedynamic_references_map(cpool->length() / 2),
592 _method_handle_invokers(cpool->length()),
593 _invokedynamic_cp_cache_map(cpool->length() / 4)
594 {
595
596 // Rewrite bytecodes - exception here exits.
597 rewrite_bytecodes(CHECK);
598
599 // Stress restoring bytecodes
600 if (StressRewriter) {
601 restore_bytecodes(THREAD);
602 rewrite_bytecodes(CHECK);
603 }
604
605 // allocate constant pool cache, now that we've seen all the bytecodes
606 make_constant_pool_cache(THREAD);
607
608 // Restore bytecodes to their unrewritten state if there are exceptions
609 // rewriting bytecodes or allocating the cpCache
610 if (HAS_PENDING_EXCEPTION) {
611 restore_bytecodes(THREAD);
612 return;
613 }
614
615 // Relocate after everything, but still do this under the is_rewritten flag,
616 // so methods with jsrs in custom class lists in aren't attempted to be
617 // rewritten in the RO section of the shared archive.
618 // Relocated bytecodes don't have to be restored, only the cp cache entries
619 int len = _methods->length();
620 for (int i = len-1; i >= 0; i--) {
621 methodHandle m(THREAD, _methods->at(i));
622
623 if (m->has_jsrs()) {
624 m = rewrite_jsrs(m, THREAD);
625 // Restore bytecodes to their unrewritten state if there are exceptions
626 // relocating bytecodes. If some are relocated, that is ok because that
627 // doesn't affect constant pool to cpCache rewriting.
628 if (HAS_PENDING_EXCEPTION) {
629 restore_bytecodes(THREAD);
630 return;
631 }
632 // Method might have gotten rewritten.
633 methods->at_put(i, m());
634 }
635 }
636 }
637