1 /*
2 * Copyright (c) 1999, 2019, 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.
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23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciConstant.hpp"
27 #include "ci/ciField.hpp"
28 #include "ci/ciKlass.hpp"
29 #include "ci/ciObjArrayKlass.hpp"
30 #include "ci/ciStreams.hpp"
31 #include "ci/ciSymbols.hpp"
32 #include "ci/ciUtilities.inline.hpp"
33 #include "runtime/handles.inline.hpp"
34
35 // ciExceptionHandlerStream
36 //
37 // Walk over some selected set of a methods exception handlers.
38
39 // ------------------------------------------------------------------
40 // ciExceptionHandlerStream::count
41 //
42 // How many exception handlers are there in this stream?
43 //
44 // Implementation note: Compiler2 needs this functionality, so I had
45 int ciExceptionHandlerStream::count() {
46 int save_pos = _pos;
47 int save_end = _end;
48
49 int count = 0;
50
51 _pos = -1;
52 _end = _method->_handler_count;
53
54
55 next();
56 while (!is_done()) {
57 count++;
58 next();
59 }
60
61 _pos = save_pos;
62 _end = save_end;
63
64 return count;
65 }
66
67 int ciExceptionHandlerStream::count_remaining() {
68 int save_pos = _pos;
69 int save_end = _end;
70
71 int count = 0;
72
73 while (!is_done()) {
74 count++;
75 next();
76 }
77
78 _pos = save_pos;
79 _end = save_end;
80
81 return count;
82 }
83
84 // ciBytecodeStream
85 //
86 // The class is used to iterate over the bytecodes of a method.
87 // It hides the details of constant pool structure/access by
88 // providing accessors for constant pool items.
89
90 // ------------------------------------------------------------------
91 // ciBytecodeStream::next_wide_or_table
92 //
93 // Special handling for switch ops
94 Bytecodes::Code ciBytecodeStream::next_wide_or_table(Bytecodes::Code bc) {
95 switch (bc) { // Check for special bytecode handling
96 case Bytecodes::_wide:
97 // Special handling for the wide bytcode
98 // Get following bytecode; do not return wide
99 assert(Bytecodes::Code(_pc[0]) == Bytecodes::_wide, "");
100 bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)_pc[1]);
101 assert(Bytecodes::wide_length_for(bc) > 2, "must make progress");
102 _pc += Bytecodes::wide_length_for(bc);
103 _was_wide = _pc; // Flag last wide bytecode found
104 assert(is_wide(), "accessor works right");
105 break;
106
107 case Bytecodes::_lookupswitch:
108 _pc++; // Skip wide bytecode
109 _pc += (_start-_pc)&3; // Word align
110 _table_base = (jint*)_pc; // Capture for later usage
111 // table_base[0] is default far_dest
112 // Table has 2 lead elements (default, length), then pairs of u4 values.
113 // So load table length, and compute address at end of table
114 _pc = (address)&_table_base[2+ 2*Bytes::get_Java_u4((address)&_table_base[1])];
115 break;
116
117 case Bytecodes::_tableswitch: {
118 _pc++; // Skip wide bytecode
119 _pc += (_start-_pc)&3; // Word align
120 _table_base = (jint*)_pc; // Capture for later usage
121 // table_base[0] is default far_dest
122 int lo = Bytes::get_Java_u4((address)&_table_base[1]);// Low bound
123 int hi = Bytes::get_Java_u4((address)&_table_base[2]);// High bound
124 int len = hi - lo + 1; // Dense table size
125 _pc = (address)&_table_base[3+len]; // Skip past table
126 break;
127 }
128
129 default:
130 fatal("unhandled bytecode");
131 }
132 return bc;
133 }
134
135 // ------------------------------------------------------------------
136 // ciBytecodeStream::reset_to_bci
137 void ciBytecodeStream::reset_to_bci( int bci ) {
138 _bc_start=_was_wide=0;
139 _pc = _start+bci;
140 }
141
142 // ------------------------------------------------------------------
143 // ciBytecodeStream::force_bci
144 void ciBytecodeStream::force_bci(int bci) {
145 if (bci < 0) {
146 reset_to_bci(0);
147 _bc_start = _start + bci;
148 _bc = EOBC();
149 } else {
150 reset_to_bci(bci);
151 next();
152 }
153 }
154
155
156 // ------------------------------------------------------------------
157 // Constant pool access
158 // ------------------------------------------------------------------
159
160 // ------------------------------------------------------------------
161 // ciBytecodeStream::get_klass_index
162 //
163 // If this bytecodes references a klass, return the index of the
164 // referenced klass.
165 int ciBytecodeStream::get_klass_index() const {
166 switch(cur_bc()) {
167 case Bytecodes::_ldc:
168 return get_index_u1();
169 case Bytecodes::_ldc_w:
170 case Bytecodes::_ldc2_w:
171 case Bytecodes::_checkcast:
172 case Bytecodes::_instanceof:
173 case Bytecodes::_anewarray:
174 case Bytecodes::_multianewarray:
175 case Bytecodes::_new:
176 case Bytecodes::_aconst_init:
177 case Bytecodes::_newarray:
178 return get_index_u2();
179 default:
180 ShouldNotReachHere();
181 return 0;
182 }
183 }
184
185 // ------------------------------------------------------------------
186 // ciBytecodeStream::get_klass
187 //
188 // If this bytecode is a new, newarray, multianewarray, instanceof,
189 // or checkcast, get the referenced klass.
190 ciKlass* ciBytecodeStream::get_klass(bool& will_link) {
191 VM_ENTRY_MARK;
192 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
193 return CURRENT_ENV->get_klass_by_index(cpool, get_klass_index(), will_link, _holder);
194 }
195
196 // ciBytecodeStream::get_klass
197 //
198 // If this bytecode is a new, newarray, multianewarray, instanceof,
199 // or checkcast, get the referenced klass. Retuns an unloaded ciKlass
200 // if the referenced klass is not accessible.
201 ciKlass* ciBytecodeStream::get_klass() {
202 bool will_link;
203 ciKlass* klass = get_klass(will_link);
204 if (!will_link && klass->is_loaded()) { // klass not accessible
205 VM_ENTRY_MARK;
206 klass = CURRENT_ENV->get_unloaded_klass(_holder, klass->name());
207 }
208 return klass;
209 }
210
211 // ------------------------------------------------------------------
212 // ciBytecodeStream::is_inline_klass
213 //
214 // Check if the klass is an inline klass.
215 bool ciBytecodeStream::has_Q_signature() const {
216 VM_ENTRY_MARK;
217 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
218 return CURRENT_ENV->has_Q_signature(cpool, get_klass_index());
219 }
220
221 // ------------------------------------------------------------------
222 // ciBytecodeStream::get_constant_raw_index
223 //
224 // If this bytecode is one of the ldc variants, get the index of the
225 // referenced constant.
226 int ciBytecodeStream::get_constant_raw_index() const {
227 // work-alike for Bytecode_loadconstant::raw_index()
228 switch (cur_bc()) {
229 case Bytecodes::_ldc:
230 return get_index_u1();
231 case Bytecodes::_ldc_w:
232 case Bytecodes::_ldc2_w:
233 return get_index_u2();
234 default:
235 ShouldNotReachHere();
236 return 0;
237 }
238 }
239
240 // ------------------------------------------------------------------
241 // ciBytecodeStream::get_constant_pool_index
242 // Decode any reference index into a regular pool index.
243 int ciBytecodeStream::get_constant_pool_index() const {
244 // work-alike for Bytecode_loadconstant::pool_index()
245 int index = get_constant_raw_index();
246 if (has_cache_index()) {
247 VM_ENTRY_MARK;
248 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
249 return cpool->object_to_cp_index(index);
250 }
251 return index;
252 }
253
254 // ------------------------------------------------------------------
255 // ciBytecodeStream::get_constant
256 //
257 // If this bytecode is one of the ldc variants, get the referenced
258 // constant.
259 ciConstant ciBytecodeStream::get_constant() {
260 VM_ENTRY_MARK;
261 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
262 int pool_index = get_constant_raw_index();
263 int cache_index = -1;
264 if (has_cache_index()) {
265 cache_index = pool_index;
266 pool_index = cpool->object_to_cp_index(cache_index);
267 } else if (cpool->tag_at(pool_index).is_dynamic_constant() ||
268 cpool->tag_at(pool_index).is_dynamic_constant_in_error()) {
269 // Condy with primitive type is not quickened, so the index into resolved reference cache should be reconstructed.
270 assert(is_java_primitive(cpool->basic_type_for_constant_at(pool_index)), "not quickened");
271 cache_index = cpool->cp_to_object_index(pool_index);
272 }
273 return CURRENT_ENV->get_constant_by_index(cpool, pool_index, cache_index, _holder);
274 }
275
276 // ------------------------------------------------------------------
277 // ciBytecodeStream::get_constant_pool_tag
278 //
279 // If this bytecode is one of the ldc variants, get the referenced
280 // constant.
281 constantTag ciBytecodeStream::get_constant_pool_tag(int index) const {
282 VM_ENTRY_MARK;
283 return _method->get_Method()->constants()->constant_tag_at(index);
284 }
285
286 // ------------------------------------------------------------------
287 // ciBytecodeStream::get_raw_pool_tag
288 //
289 constantTag ciBytecodeStream::get_raw_pool_tag_at(int index) const {
290 VM_ENTRY_MARK;
291 return _method->get_Method()->constants()->tag_at(index);
292 }
293
294 // ------------------------------------------------------------------
295 // ciBytecodeStream::get_basic_type_for_constant_at
296 //
297 BasicType ciBytecodeStream::get_basic_type_for_constant_at(int index) const {
298 VM_ENTRY_MARK;
299 return _method->get_Method()->constants()->basic_type_for_constant_at(index);
300 }
301
302 // ------------------------------------------------------------------
303 // ciBytecodeStream::get_field_index
304 //
305 // If this is a field access bytecode, get the constant pool
306 // index of the referenced field.
307 int ciBytecodeStream::get_field_index() {
308 assert(cur_bc() == Bytecodes::_getfield ||
309 cur_bc() == Bytecodes::_putfield ||
310 cur_bc() == Bytecodes::_getstatic ||
311 cur_bc() == Bytecodes::_putstatic ||
312 cur_bc() == Bytecodes::_withfield, "wrong bc");
313 return get_index_u2_cpcache();
314 }
315
316
317 // ------------------------------------------------------------------
318 // ciBytecodeStream::get_field
319 //
320 // If this bytecode is one of get_field, get_static, put_field,
321 // or put_static, get the referenced field.
322 ciField* ciBytecodeStream::get_field(bool& will_link) {
323 ciField* f = CURRENT_ENV->get_field_by_index(_holder, get_field_index());
324 will_link = f->will_link(_method, _bc);
325 return f;
326 }
327
328
329 // ------------------------------------------------------------------
330 // ciBytecodeStream::get_declared_field_holder
331 //
332 // Get the declared holder of the currently referenced field.
333 //
334 // Usage note: the holder() of a ciField class returns the canonical
335 // holder of the field, rather than the holder declared in the
336 // bytecodes.
337 //
338 // There is no "will_link" result passed back. The user is responsible
339 // for checking linkability when retrieving the associated field.
340 ciInstanceKlass* ciBytecodeStream::get_declared_field_holder() {
341 VM_ENTRY_MARK;
342 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
343 int holder_index = get_field_holder_index();
344 bool ignore;
345 return CURRENT_ENV->get_klass_by_index(cpool, holder_index, ignore, _holder)
346 ->as_instance_klass();
347 }
348
349 // ------------------------------------------------------------------
350 // ciBytecodeStream::get_field_holder_index
351 //
352 // Get the constant pool index of the declared holder of the field
353 // referenced by the current bytecode. Used for generating
354 // deoptimization information.
355 int ciBytecodeStream::get_field_holder_index() {
356 GUARDED_VM_ENTRY(
357 ConstantPool* cpool = _holder->get_instanceKlass()->constants();
358 return cpool->klass_ref_index_at(get_field_index());
359 )
360 }
361
362 // ------------------------------------------------------------------
363 // ciBytecodeStream::get_method_index
364 //
365 // If this is a method invocation bytecode, get the constant pool
366 // index of the invoked method.
367 int ciBytecodeStream::get_method_index() {
368 assert(Bytecodes::is_invoke(cur_bc()), "invalid bytecode: %s", Bytecodes::name(cur_bc()));
369 if (has_index_u4())
370 return get_index_u4(); // invokedynamic
371 return get_index_u2_cpcache();
372 }
373
374 // ------------------------------------------------------------------
375 // ciBytecodeStream::get_method
376 //
377 // If this is a method invocation bytecode, get the invoked method.
378 // Additionally return the declared signature to get more concrete
379 // type information if required (Cf. invokedynamic and invokehandle).
380 ciMethod* ciBytecodeStream::get_method(bool& will_link, ciSignature* *declared_signature_result) {
381 VM_ENTRY_MARK;
382 ciEnv* env = CURRENT_ENV;
383 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
384 ciMethod* m = env->get_method_by_index(cpool, get_method_index(), cur_bc(), _holder);
385 will_link = m->is_loaded();
386
387 // Use the signature stored in the CP cache to create a signature
388 // with correct types (in respect to class loaders).
389 //
390 // In classic Java (before Java 7) there is never the slightest
391 // difference between the signature at the call site and that of the
392 // method. Such a difference would have been a type error in the
393 // JVM.
394 //
395 // Now there are a few circumstances where the signature of a call
396 // site (which controls the outgoing stacked arguments) can differ
397 // from the signature of the method (which controls the receipt of
398 // those arguments at the method entry point).
399 //
400 // A. The signatures can differ if the callee is a static method and
401 // the caller thinks it is calling a non-static method (VH.get).
402 // This requires the method signature to have an explicit leading
403 // argument for the implicit 'this', not present at the call site.
404 //
405 // B. The call site can have less specific parameter types than the
406 // method, allowing loosely-typed code to handle strongly-typed
407 // methods. This happens with linkToStatic and related linker
408 // commands. Obviously the loosely-typed code has to ensure that
409 // the strongly typed method's invariants are respected, and this is
410 // done by issuing dynamic casts.
411 //
412 // C. The call site can have more specific parameter types than the
413 // method, allowing loosely-typed methods to handle strongly-typed
414 // requests.
415 //
416 // D. There are corresponding effects with return values, such as
417 // boolean method returning an int to an int-receiving call site,
418 // even though the method thought it returned just a boolean.
419 //
420 // E. The calling sequence at a particular call site may add an
421 // "appendix" argument not mentioned in the call site signature. It
422 // is expected by the method signature, though, and this adds to the
423 // method's arity, even after 'this' parameter effects (A) are
424 // discounted. Appendixes are used by invokehandle and
425 // invokedynamic instructions.
426 //
427 // F. A linker method (linkToStatic, etc.) can also take an extra
428 // argument, a MemberName which routes the call to a concrete
429 // strongly-typed method. In this case the linker method may also
430 // differ in any of the ways A-D. The eventual method will ignore
431 // the presence of the extra argument.
432 //
433 // None of these changes to calling sequences requires an argument
434 // to be moved or reformatted in any way. This works because all
435 // references look alike to the JVM, as do all primitives (except
436 // float/long/double). Another required property of the JVM is
437 // that, if a trailing argument is added or dropped, the placement
438 // of other arguments does not change. This allows cases E and F to
439 // work smoothly, against without any moving or reformatting,
440 // despite the arity change.
441 //
442 if (has_local_signature()) {
443 Symbol* local_signature = cpool->symbol_at(get_method_signature_index(cpool));
444 ciSymbol* sig_sym = env->get_symbol(local_signature);
445 ciKlass* pool_holder = env->get_klass(cpool->pool_holder());
446 ciSignature* call_site_sig = new (env->arena()) ciSignature(pool_holder, cpool, sig_sym);
447 // Examples of how the call site signature can differ from the method's own signature:
448 //
449 // meth = static jboolean java.lang.invoke.VarHandleGuards.guard_LII_Z(jobject, jobject, jint, jint, jobject)
450 // msig = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/VarHandle$AccessDescriptor;)Z
451 // call = (Ljava/util/concurrent/locks/AbstractQueuedSynchronizer;II)Z
452 //
453 // meth = static jobject java.lang.invoke.LambdaForm$MH/0x0000000800066840.linkToTargetMethod(jobject, jobject)
454 // msig = (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
455 // call = (Ljava/lang/String;)Ljava/util/function/Predicate;
456 //
457 (*declared_signature_result) = call_site_sig;
458
459 } else {
460 // We can just use the method's own signature. It may differ from the call site, but not by much.
461 //
462 // Examples of how the call site signature can differ from the method's signature:
463 //
464 // meth = static final native jint java.lang.invoke.MethodHandle.linkToStatic(jobject, jobject, jint, jint, jobject)
465 // msig = (Ljava/lang/Object;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)I
466 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)Z
467 //
468 // meth = final native jint java.lang.invoke.MethodHandle.invokeBasic(jobject, jobject, jint, jint)
469 // msig = (Ljava/lang/Object;Ljava/lang/Object;II)I
470 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;II)Z
471 //
472 (*declared_signature_result) = m->signature();
473 }
474 return m;
475 }
476
477 // ------------------------------------------------------------------
478 // ciBytecodeStream::has_appendix
479 //
480 // Returns true if there is an appendix argument stored in the
481 // constant pool cache at the current bci.
482 bool ciBytecodeStream::has_appendix() {
483 VM_ENTRY_MARK;
484 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
485 return ConstantPool::has_appendix_at_if_loaded(cpool, get_method_index());
486 }
487
488 // ------------------------------------------------------------------
489 // ciBytecodeStream::get_appendix
490 //
491 // Return the appendix argument stored in the constant pool cache at
492 // the current bci.
493 ciObject* ciBytecodeStream::get_appendix() {
494 VM_ENTRY_MARK;
495 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
496 oop appendix_oop = ConstantPool::appendix_at_if_loaded(cpool, get_method_index());
497 return CURRENT_ENV->get_object(appendix_oop);
498 }
499
500 // ------------------------------------------------------------------
501 // ciBytecodeStream::has_local_signature
502 //
503 // Returns true if the method stored in the constant
504 // pool cache at the current bci has a local signature.
505 bool ciBytecodeStream::has_local_signature() {
506 GUARDED_VM_ENTRY(
507 constantPoolHandle cpool(Thread::current(), _method->get_Method()->constants());
508 return ConstantPool::has_local_signature_at_if_loaded(cpool, get_method_index());
509 )
510 }
511
512 // ------------------------------------------------------------------
513 // ciBytecodeStream::get_declared_method_holder
514 //
515 // Get the declared holder of the currently referenced method.
516 //
517 // Usage note: the holder() of a ciMethod class returns the canonical
518 // holder of the method, rather than the holder declared in the
519 // bytecodes.
520 //
521 // There is no "will_link" result passed back. The user is responsible
522 // for checking linkability when retrieving the associated method.
523 ciKlass* ciBytecodeStream::get_declared_method_holder() {
524 VM_ENTRY_MARK;
525 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
526 bool ignore;
527 // report as MethodHandle for invokedynamic, which is syntactically classless
528 if (cur_bc() == Bytecodes::_invokedynamic) {
529 return CURRENT_ENV->MethodHandle_klass();
530 }
531 return CURRENT_ENV->get_klass_by_index(cpool, get_method_holder_index(), ignore, _holder);
532 }
533
534 // ------------------------------------------------------------------
535 // ciBytecodeStream::get_method_holder_index
536 //
537 // Get the constant pool index of the declared holder of the method
538 // referenced by the current bytecode. Used for generating
539 // deoptimization information.
540 int ciBytecodeStream::get_method_holder_index() {
541 ConstantPool* cpool = _method->get_Method()->constants();
542 return cpool->klass_ref_index_at(get_method_index());
543 }
544
545 // ------------------------------------------------------------------
546 // ciBytecodeStream::get_method_signature_index
547 //
548 // Get the constant pool index of the signature of the method
549 // referenced by the current bytecode. Used for generating
550 // deoptimization information.
551 int ciBytecodeStream::get_method_signature_index(const constantPoolHandle& cpool) {
552 GUARDED_VM_ENTRY(
553 const int method_index = get_method_index();
554 const int name_and_type_index = cpool->name_and_type_ref_index_at(method_index);
555 return cpool->signature_ref_index_at(name_and_type_index);
556 )
557 }
558