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