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