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