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