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.
22 *
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::_newarray:
177 return get_index_u2();
178 default:
179 ShouldNotReachHere();
180 return 0;
181 }
182 }
183
184 // ------------------------------------------------------------------
185 // ciBytecodeStream::get_klass
186 //
187 // If this bytecode is a new, newarray, multianewarray, instanceof,
188 // or checkcast, get the referenced klass.
189 ciKlass* ciBytecodeStream::get_klass(bool& will_link) {
190 VM_ENTRY_MARK;
191 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
192 return CURRENT_ENV->get_klass_by_index(cpool, get_klass_index(), will_link, _holder);
193 }
194
195 // ciBytecodeStream::get_klass
196 //
197 // If this bytecode is a new, newarray, multianewarray, instanceof,
198 // or checkcast, get the referenced klass. Retuns an unloaded ciKlass
199 // if the referenced klass is not accessible.
200 ciKlass* ciBytecodeStream::get_klass() {
201 bool will_link;
202 ciKlass* klass = get_klass(will_link);
203 if (!will_link && klass->is_loaded()) { // klass not accessible
204 VM_ENTRY_MARK;
205 klass = CURRENT_ENV->get_unloaded_klass(_holder, klass->name());
206 }
207 return klass;
208 }
209
210 // ------------------------------------------------------------------
211 // ciBytecodeStream::get_constant_raw_index
212 //
213 // If this bytecode is one of the ldc variants, get the index of the
214 // referenced constant.
215 int ciBytecodeStream::get_constant_raw_index() const {
216 // work-alike for Bytecode_loadconstant::raw_index()
217 switch (cur_bc()) {
218 case Bytecodes::_ldc:
219 return get_index_u1();
220 case Bytecodes::_ldc_w:
221 case Bytecodes::_ldc2_w:
222 return get_index_u2();
223 default:
224 ShouldNotReachHere();
225 return 0;
226 }
227 }
228
229 // ------------------------------------------------------------------
230 // ciBytecodeStream::get_constant_pool_index
231 // Decode any reference index into a regular pool index.
232 int ciBytecodeStream::get_constant_pool_index() const {
233 // work-alike for Bytecode_loadconstant::pool_index()
234 int index = get_constant_raw_index();
235 if (has_cache_index()) {
236 VM_ENTRY_MARK;
237 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
238 return cpool->object_to_cp_index(index);
239 }
240 return index;
241 }
242
243 // ------------------------------------------------------------------
244 // ciBytecodeStream::get_constant
245 //
246 // If this bytecode is one of the ldc variants, get the referenced
247 // constant.
248 ciConstant ciBytecodeStream::get_constant() {
249 VM_ENTRY_MARK;
250 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
251 int pool_index = get_constant_raw_index();
252 int cache_index = -1;
253 if (has_cache_index()) {
254 cache_index = pool_index;
255 pool_index = cpool->object_to_cp_index(cache_index);
256 } else if (cpool->tag_at(pool_index).is_dynamic_constant() ||
257 cpool->tag_at(pool_index).is_dynamic_constant_in_error()) {
258 // Condy with primitive type is not quickened, so the index into resolved reference cache should be reconstructed.
259 assert(is_java_primitive(cpool->basic_type_for_constant_at(pool_index)), "not quickened");
260 cache_index = cpool->cp_to_object_index(pool_index);
261 }
262 return CURRENT_ENV->get_constant_by_index(cpool, pool_index, cache_index, _holder);
263 }
264
265 // ------------------------------------------------------------------
266 // ciBytecodeStream::get_constant_pool_tag
267 //
268 // If this bytecode is one of the ldc variants, get the referenced
269 // constant.
270 constantTag ciBytecodeStream::get_constant_pool_tag(int index) const {
271 VM_ENTRY_MARK;
272 return _method->get_Method()->constants()->constant_tag_at(index);
273 }
274
275 // ------------------------------------------------------------------
276 // ciBytecodeStream::get_raw_pool_tag
277 //
278 constantTag ciBytecodeStream::get_raw_pool_tag_at(int index) const {
279 VM_ENTRY_MARK;
280 return _method->get_Method()->constants()->tag_at(index);
281 }
282
283 // ------------------------------------------------------------------
284 // ciBytecodeStream::get_basic_type_for_constant_at
285 //
286 BasicType ciBytecodeStream::get_basic_type_for_constant_at(int index) const {
287 VM_ENTRY_MARK;
288 return _method->get_Method()->constants()->basic_type_for_constant_at(index);
289 }
290
291 // ------------------------------------------------------------------
292 // ciBytecodeStream::get_field_index
293 //
294 // If this is a field access bytecode, get the constant pool
295 // index of the referenced field.
296 int ciBytecodeStream::get_field_index() {
297 assert(cur_bc() == Bytecodes::_getfield ||
298 cur_bc() == Bytecodes::_putfield ||
299 cur_bc() == Bytecodes::_getstatic ||
300 cur_bc() == Bytecodes::_putstatic, "wrong bc");
301 return get_index_u2_cpcache();
302 }
303
304
305 // ------------------------------------------------------------------
306 // ciBytecodeStream::get_field
307 //
308 // If this bytecode is one of get_field, get_static, put_field,
309 // or put_static, get the referenced field.
310 ciField* ciBytecodeStream::get_field(bool& will_link) {
311 ciField* f = CURRENT_ENV->get_field_by_index(_holder, get_field_index());
312 will_link = f->will_link(_method, _bc);
313 return f;
314 }
315
316
317 // ------------------------------------------------------------------
318 // ciBytecodeStream::get_declared_field_holder
319 //
320 // Get the declared holder of the currently referenced field.
321 //
322 // Usage note: the holder() of a ciField class returns the canonical
323 // holder of the field, rather than the holder declared in the
324 // bytecodes.
325 //
326 // There is no "will_link" result passed back. The user is responsible
327 // for checking linkability when retrieving the associated field.
328 ciInstanceKlass* ciBytecodeStream::get_declared_field_holder() {
329 VM_ENTRY_MARK;
330 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
331 int holder_index = get_field_holder_index();
332 bool ignore;
333 return CURRENT_ENV->get_klass_by_index(cpool, holder_index, ignore, _holder)
334 ->as_instance_klass();
335 }
336
337 // ------------------------------------------------------------------
338 // ciBytecodeStream::get_field_holder_index
339 //
340 // Get the constant pool index of the declared holder of the field
341 // referenced by the current bytecode. Used for generating
342 // deoptimization information.
343 int ciBytecodeStream::get_field_holder_index() {
344 GUARDED_VM_ENTRY(
345 ConstantPool* cpool = _holder->get_instanceKlass()->constants();
346 return cpool->klass_ref_index_at(get_field_index());
347 )
348 }
349
350 // ------------------------------------------------------------------
351 // ciBytecodeStream::get_method_index
352 //
353 // If this is a method invocation bytecode, get the constant pool
354 // index of the invoked method.
355 int ciBytecodeStream::get_method_index() {
356 assert(Bytecodes::is_invoke(cur_bc()), "invalid bytecode: %s", Bytecodes::name(cur_bc()));
357 if (has_index_u4())
358 return get_index_u4(); // invokedynamic
359 return get_index_u2_cpcache();
360 }
361
362 // ------------------------------------------------------------------
363 // ciBytecodeStream::get_method
364 //
365 // If this is a method invocation bytecode, get the invoked method.
366 // Additionally return the declared signature to get more concrete
367 // type information if required (Cf. invokedynamic and invokehandle).
368 ciMethod* ciBytecodeStream::get_method(bool& will_link, ciSignature* *declared_signature_result) {
369 VM_ENTRY_MARK;
370 ciEnv* env = CURRENT_ENV;
371 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
372 ciMethod* m = env->get_method_by_index(cpool, get_method_index(), cur_bc(), _holder);
373 will_link = m->is_loaded();
374
375 // Use the signature stored in the CP cache to create a signature
376 // with correct types (in respect to class loaders).
377 //
378 // In classic Java (before Java 7) there is never the slightest
379 // difference between the signature at the call site and that of the
380 // method. Such a difference would have been a type error in the
381 // JVM.
382 //
383 // Now there are a few circumstances where the signature of a call
384 // site (which controls the outgoing stacked arguments) can differ
385 // from the signature of the method (which controls the receipt of
386 // those arguments at the method entry point).
387 //
388 // A. The signatures can differ if the callee is a static method and
389 // the caller thinks it is calling a non-static method (VH.get).
390 // This requires the method signature to have an explicit leading
391 // argument for the implicit 'this', not present at the call site.
392 //
393 // B. The call site can have less specific parameter types than the
394 // method, allowing loosely-typed code to handle strongly-typed
395 // methods. This happens with linkToStatic and related linker
396 // commands. Obviously the loosely-typed code has to ensure that
397 // the strongly typed method's invariants are respected, and this is
398 // done by issuing dynamic casts.
399 //
400 // C. The call site can have more specific parameter types than the
401 // method, allowing loosely-typed methods to handle strongly-typed
402 // requests.
403 //
404 // D. There are corresponding effects with return values, such as
405 // boolean method returning an int to an int-receiving call site,
406 // even though the method thought it returned just a boolean.
407 //
408 // E. The calling sequence at a particular call site may add an
409 // "appendix" argument not mentioned in the call site signature. It
410 // is expected by the method signature, though, and this adds to the
411 // method's arity, even after 'this' parameter effects (A) are
412 // discounted. Appendixes are used by invokehandle and
413 // invokedynamic instructions.
414 //
415 // F. A linker method (linkToStatic, etc.) can also take an extra
416 // argument, a MemberName which routes the call to a concrete
417 // strongly-typed method. In this case the linker method may also
418 // differ in any of the ways A-D. The eventual method will ignore
419 // the presence of the extra argument.
420 //
421 // None of these changes to calling sequences requires an argument
422 // to be moved or reformatted in any way. This works because all
423 // references look alike to the JVM, as do all primitives (except
424 // float/long/double). Another required property of the JVM is
425 // that, if a trailing argument is added or dropped, the placement
426 // of other arguments does not change. This allows cases E and F to
427 // work smoothly, against without any moving or reformatting,
428 // despite the arity change.
429 //
430 if (has_local_signature()) {
431 Symbol* local_signature = cpool->symbol_at(get_method_signature_index(cpool));
432 ciSymbol* sig_sym = env->get_symbol(local_signature);
433 ciKlass* pool_holder = env->get_klass(cpool->pool_holder());
434 ciSignature* call_site_sig = new (env->arena()) ciSignature(pool_holder, cpool, sig_sym);
435 // Examples of how the call site signature can differ from the method's own signature:
436 //
437 // meth = static jboolean java.lang.invoke.VarHandleGuards.guard_LII_Z(jobject, jobject, jint, jint, jobject)
438 // msig = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/VarHandle$AccessDescriptor;)Z
439 // call = (Ljava/util/concurrent/locks/AbstractQueuedSynchronizer;II)Z
440 //
441 // meth = static jobject java.lang.invoke.LambdaForm$MH/0x0000000800066840.linkToTargetMethod(jobject, jobject)
442 // msig = (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
443 // call = (Ljava/lang/String;)Ljava/util/function/Predicate;
444 //
445 (*declared_signature_result) = call_site_sig;
446
447 } else {
448 // We can just use the method's own signature. It may differ from the call site, but not by much.
449 //
450 // Examples of how the call site signature can differ from the method's signature:
451 //
452 // meth = static final native jint java.lang.invoke.MethodHandle.linkToStatic(jobject, jobject, jint, jint, jobject)
453 // msig = (Ljava/lang/Object;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)I
454 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)Z
455 //
456 // meth = final native jint java.lang.invoke.MethodHandle.invokeBasic(jobject, jobject, jint, jint)
457 // msig = (Ljava/lang/Object;Ljava/lang/Object;II)I
458 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;II)Z
459 //
460 (*declared_signature_result) = m->signature();
461 }
462 return m;
463 }
464
465 // ------------------------------------------------------------------
466 // ciBytecodeStream::has_appendix
467 //
468 // Returns true if there is an appendix argument stored in the
469 // constant pool cache at the current bci.
470 bool ciBytecodeStream::has_appendix() {
471 VM_ENTRY_MARK;
472 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
473 return ConstantPool::has_appendix_at_if_loaded(cpool, get_method_index());
474 }
475
476 // ------------------------------------------------------------------
477 // ciBytecodeStream::get_appendix
478 //
479 // Return the appendix argument stored in the constant pool cache at
480 // the current bci.
481 ciObject* ciBytecodeStream::get_appendix() {
482 VM_ENTRY_MARK;
483 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
484 oop appendix_oop = ConstantPool::appendix_at_if_loaded(cpool, get_method_index());
485 return CURRENT_ENV->get_object(appendix_oop);
486 }
487
488 // ------------------------------------------------------------------
489 // ciBytecodeStream::has_local_signature
490 //
491 // Returns true if the method stored in the constant
492 // pool cache at the current bci has a local signature.
493 bool ciBytecodeStream::has_local_signature() {
494 GUARDED_VM_ENTRY(
495 constantPoolHandle cpool(Thread::current(), _method->get_Method()->constants());
496 return ConstantPool::has_local_signature_at_if_loaded(cpool, get_method_index());
497 )
498 }
499
500 // ------------------------------------------------------------------
501 // ciBytecodeStream::get_declared_method_holder
502 //
503 // Get the declared holder of the currently referenced method.
504 //
505 // Usage note: the holder() of a ciMethod class returns the canonical
506 // holder of the method, rather than the holder declared in the
507 // bytecodes.
508 //
509 // There is no "will_link" result passed back. The user is responsible
510 // for checking linkability when retrieving the associated method.
511 ciKlass* ciBytecodeStream::get_declared_method_holder() {
512 VM_ENTRY_MARK;
513 constantPoolHandle cpool(THREAD, _method->get_Method()->constants());
514 bool ignore;
515 // report as MethodHandle for invokedynamic, which is syntactically classless
516 if (cur_bc() == Bytecodes::_invokedynamic) {
517 return CURRENT_ENV->MethodHandle_klass();
518 }
519 return CURRENT_ENV->get_klass_by_index(cpool, get_method_holder_index(), ignore, _holder);
520 }
521
522 // ------------------------------------------------------------------
523 // ciBytecodeStream::get_method_holder_index
524 //
525 // Get the constant pool index of the declared holder of the method
526 // referenced by the current bytecode. Used for generating
527 // deoptimization information.
528 int ciBytecodeStream::get_method_holder_index() {
529 ConstantPool* cpool = _method->get_Method()->constants();
530 return cpool->klass_ref_index_at(get_method_index());
531 }
532
533 // ------------------------------------------------------------------
534 // ciBytecodeStream::get_method_signature_index
535 //
536 // Get the constant pool index of the signature of the method
537 // referenced by the current bytecode. Used for generating
538 // deoptimization information.
539 int ciBytecodeStream::get_method_signature_index(const constantPoolHandle& cpool) {
540 GUARDED_VM_ENTRY(
541 const int method_index = get_method_index();
542 const int name_and_type_index = cpool->name_and_type_ref_index_at(method_index);
543 return cpool->signature_ref_index_at(name_and_type_index);
544 )
545 }
546