1 /*
2 * Copyright (c) 2005, 2024, 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
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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).
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23 */
24
25 #ifndef SHARE_CODE_DEPENDENCIES_HPP
26 #define SHARE_CODE_DEPENDENCIES_HPP
27
28 #include "ci/ciCallSite.hpp"
29 #include "ci/ciKlass.hpp"
30 #include "ci/ciMethod.hpp"
31 #include "ci/ciMethodHandle.hpp"
32 #include "code/compressedStream.hpp"
33 #include "code/nmethod.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "runtime/safepointVerifiers.hpp"
36 #include "utilities/growableArray.hpp"
37
38 //** Dependencies represent assertions (approximate invariants) within
39 // the runtime system, e.g. class hierarchy changes. An example is an
40 // assertion that a given method is not overridden; another example is
41 // that a type has only one concrete subtype. Compiled code which
42 // relies on such assertions must be discarded if they are overturned
43 // by changes in the runtime system. We can think of these assertions
44 // as approximate invariants, because we expect them to be overturned
45 // very infrequently. We are willing to perform expensive recovery
46 // operations when they are overturned. The benefit, of course, is
47 // performing optimistic optimizations (!) on the object code.
48 //
49 // Changes in the class hierarchy due to dynamic linking or
50 // class evolution can violate dependencies. There is enough
51 // indexing between classes and nmethods to make dependency
52 // checking reasonably efficient.
53
54 class ciEnv;
55 class nmethod;
56 class OopRecorder;
57 class xmlStream;
58 class CompileLog;
59 class CompileTask;
60 class DepChange;
61 class KlassDepChange;
62 class NewKlassDepChange;
63 class KlassInitDepChange;
64 class CallSiteDepChange;
65 class NoSafepointVerifier;
66
67 class Dependencies: public ResourceObj {
68 public:
69 // Note: In the comments on dependency types, most uses of the terms
70 // subtype and supertype are used in a "non-strict" or "inclusive"
71 // sense, and are starred to remind the reader of this fact.
72 // Strict uses of the terms use the word "proper".
73 //
74 // Specifically, every class is its own subtype* and supertype*.
75 // (This trick is easier than continually saying things like "Y is a
76 // subtype of X or X itself".)
77 //
78 // Sometimes we write X > Y to mean X is a proper supertype of Y.
79 // The notation X > {Y, Z} means X has proper subtypes Y, Z.
80 // The notation X.m > Y means that Y inherits m from X, while
81 // X.m > Y.m means Y overrides X.m. A star denotes abstractness,
82 // as *I > A, meaning (abstract) interface I is a super type of A,
83 // or A.*m > B.m, meaning B.m implements abstract method A.m.
84 //
85 // In this module, the terms "subtype" and "supertype" refer to
86 // Java-level reference type conversions, as detected by
87 // "instanceof" and performed by "checkcast" operations. The method
88 // Klass::is_subtype_of tests these relations. Note that "subtype"
89 // is richer than "subclass" (as tested by Klass::is_subclass_of),
90 // since it takes account of relations involving interface and array
91 // types.
92 //
93 // To avoid needless complexity, dependencies involving array types
94 // are not accepted. If you need to make an assertion about an
95 // array type, make the assertion about its corresponding element
96 // types. Any assertion that might change about an array type can
97 // be converted to an assertion about its element type.
98 //
99 // Most dependencies are evaluated over a "context type" CX, which
100 // stands for the set Subtypes(CX) of every Java type that is a subtype*
101 // of CX. When the system loads a new class or interface N, it is
102 // responsible for re-evaluating changed dependencies whose context
103 // type now includes N, that is, all super types of N.
104 //
105 enum DepType {
106 // _type is initially set to -1, to prevent "already at end" assert
107 undefined_dependency = -1,
108
109 end_marker = 0,
110
111 // An 'evol' dependency simply notes that the contents of the
112 // method were used. If it evolves (is replaced), the nmethod
113 // must be recompiled. No other dependencies are implied.
114 evol_method,
115 FIRST_TYPE = evol_method,
116
117 // A context type CX is a leaf it if has no proper subtype.
118 leaf_type,
119
120 // An abstract class CX has exactly one concrete subtype CC.
121 abstract_with_unique_concrete_subtype,
122
123 // Given a method M1 and a context class CX, the set MM(CX, M1) of
124 // "concrete matching methods" in CX of M1 is the set of every
125 // concrete M2 for which it is possible to create an invokevirtual
126 // or invokeinterface call site that can reach either M1 or M2.
127 // That is, M1 and M2 share a name, signature, and vtable index.
128 // We wish to notice when the set MM(CX, M1) is just {M1}, or
129 // perhaps a set of two {M1,M2}, and issue dependencies on this.
130
131 // The set MM(CX, M1) can be computed by starting with any matching
132 // concrete M2 that is inherited into CX, and then walking the
133 // subtypes* of CX looking for concrete definitions.
134
135 // The parameters to this dependency are the method M1 and the
136 // context class CX. M1 must be either inherited in CX or defined
137 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater
138 // than {M1}.
139 unique_concrete_method_2, // one unique concrete method under CX
140
141 // In addition to the method M1 and the context class CX, the parameters
142 // to this dependency are the resolved class RC1 and the
143 // resolved method RM1. It asserts that MM(CX, M1, RC1, RM1)
144 // is no greater than {M1}. RC1 and RM1 are used to improve the precision
145 // of the analysis.
146 unique_concrete_method_4, // one unique concrete method under CX
147
148 // This dependency asserts that interface CX has a unique implementor class.
149 unique_implementor, // one unique implementor under CX
150
151 // This dependency asserts that no instances of class or it's
152 // subclasses require finalization registration.
153 no_finalizable_subclasses,
154
155 // This dependency asserts when the CallSite.target value changed.
156 call_site_target_value,
157
158 TYPE_LIMIT
159 };
160 enum {
161 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
162
163 // handy categorizations of dependency types:
164 all_types = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE),
165
166 non_klass_types = (1 << call_site_target_value),
167 klass_types = all_types & ~non_klass_types,
168
169 non_ctxk_types = (1 << evol_method) | (1 << call_site_target_value),
170 implicit_ctxk_types = 0,
171 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
172
173 max_arg_count = 4, // current maximum number of arguments (incl. ctxk)
174
175 // A "context type" is a class or interface that
176 // provides context for evaluating a dependency.
177 // When present, it is one of the arguments (dep_context_arg).
178 //
179 // If a dependency does not have a context type, there is a
180 // default context, depending on the type of the dependency.
181 // This bit signals that a default context has been compressed away.
182 default_context_type_bit = (1<<LG2_TYPE_LIMIT)
183 };
184
185 static const char* dep_name(DepType dept);
186 static int dep_args(DepType dept);
187
188 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); }
189
190 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); }
191 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); }
192
193 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; }
194 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; }
195
196 static void check_valid_dependency_type(DepType dept);
197
198 #if INCLUDE_JVMCI
199 // A Metadata* or object value recorded in an OopRecorder
200 class DepValue {
201 private:
202 // Unique identifier of the value within the associated OopRecorder that
203 // encodes both the category of the value (0: invalid, positive: metadata, negative: object)
204 // and the index within a category specific array (metadata: index + 1, object: -(index + 1))
205 int _id;
206
207 public:
208 DepValue() : _id(0) {}
209 DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = nullptr) {
210 assert(candidate == nullptr || candidate->is_metadata(), "oops");
211 if (candidate != nullptr && candidate->as_metadata(rec) == metadata) {
212 _id = candidate->_id;
213 } else {
214 _id = rec->find_index(metadata) + 1;
215 }
216 }
217 DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = nullptr) {
218 assert(candidate == nullptr || candidate->is_object(), "oops");
219 if (candidate != nullptr && candidate->as_object(rec) == obj) {
220 _id = candidate->_id;
221 } else {
222 _id = -(rec->find_index(obj) + 1);
223 }
224 }
225
226 // Used to sort values in ascending order of index() with metadata values preceding object values
227 int sort_key() const { return -_id; }
228
229 bool operator == (const DepValue& other) const { return other._id == _id; }
230
231 bool is_valid() const { return _id != 0; }
232 int index() const { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; }
233 bool is_metadata() const { assert(is_valid(), "oops"); return _id > 0; }
234 bool is_object() const { assert(is_valid(), "oops"); return _id < 0; }
235
236 Metadata* as_metadata(OopRecorder* rec) const { assert(is_metadata(), "oops"); return rec->metadata_at(index()); }
237 Klass* as_klass(OopRecorder* rec) const {
238 Metadata* m = as_metadata(rec);
239 assert(m != nullptr, "as_metadata returned nullptr");
240 assert(m->is_klass(), "oops");
241 return (Klass*) m;
242 }
243 Method* as_method(OopRecorder* rec) const {
244 Metadata* m = as_metadata(rec);
245 assert(m != nullptr, "as_metadata returned nullptr");
246 assert(m->is_method(), "oops");
247 return (Method*) m;
248 }
249 jobject as_object(OopRecorder* rec) const { assert(is_object(), "oops"); return rec->oop_at(index()); }
250 };
251 #endif // INCLUDE_JVMCI
252
253 private:
254 // State for writing a new set of dependencies:
255 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept))
256 GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT];
257 #if INCLUDE_JVMCI
258 bool _using_dep_values;
259 GrowableArray<DepValue>* _dep_values[TYPE_LIMIT];
260 #endif
261
262 static const char* _dep_name[TYPE_LIMIT];
263 static int _dep_args[TYPE_LIMIT];
264
265 static bool dept_in_mask(DepType dept, int mask) {
266 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0;
267 }
268
269 bool note_dep_seen(int dept, ciBaseObject* x) {
270 assert(dept < BitsPerInt, "oob");
271 int x_id = x->ident();
272 assert(_dep_seen != nullptr, "deps must be writable");
273 int seen = _dep_seen->at_grow(x_id, 0);
274 _dep_seen->at_put(x_id, seen | (1<<dept));
275 // return true if we've already seen dept/x
276 return (seen & (1<<dept)) != 0;
277 }
278
279 #if INCLUDE_JVMCI
280 bool note_dep_seen(int dept, DepValue x) {
281 assert(dept < BitsPerInt, "oops");
282 // place metadata deps at even indexes, object deps at odd indexes
283 int x_id = x.is_metadata() ? x.index() * 2 : (x.index() * 2) + 1;
284 assert(_dep_seen != nullptr, "deps must be writable");
285 int seen = _dep_seen->at_grow(x_id, 0);
286 _dep_seen->at_put(x_id, seen | (1<<dept));
287 // return true if we've already seen dept/x
288 return (seen & (1<<dept)) != 0;
289 }
290 #endif
291
292 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
293 int ctxk_i, ciKlass* ctxk);
294 #if INCLUDE_JVMCI
295 bool maybe_merge_ctxk(GrowableArray<DepValue>* deps,
296 int ctxk_i, DepValue ctxk);
297 #endif
298
299 void sort_all_deps();
300 size_t estimate_size_in_bytes();
301
302 // Initialize _deps, etc.
303 void initialize(ciEnv* env);
304
305 // State for making a new set of dependencies:
306 OopRecorder* _oop_recorder;
307
308 // Logging support
309 CompileLog* _log;
310
311 address _content_bytes; // everything but the oop references, encoded
312 size_t _size_in_bytes;
313
314 public:
315 // Make a new empty dependencies set.
316 Dependencies(ciEnv* env) {
317 initialize(env);
318 }
319 #if INCLUDE_JVMCI
320 Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log);
321 #endif
322
323 private:
324 // Check for a valid context type.
325 // Enforce the restriction against array types.
326 static void check_ctxk(ciKlass* ctxk) {
327 assert(ctxk->is_instance_klass(), "java types only");
328 }
329 static void check_ctxk_concrete(ciKlass* ctxk) {
330 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete");
331 }
332 static void check_ctxk_abstract(ciKlass* ctxk) {
333 check_ctxk(ctxk);
334 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract");
335 }
336 static void check_unique_method(ciKlass* ctxk, ciMethod* m) {
337 assert(!m->can_be_statically_bound(ctxk->as_instance_klass()) || ctxk->is_interface(), "redundant");
338 }
339 static void check_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk) {
340 assert(ctxk->implementor() == uniqk, "not a unique implementor");
341 }
342
343 void assert_common_1(DepType dept, ciBaseObject* x);
344 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1);
345 void assert_common_4(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2, ciBaseObject* x3);
346
347 public:
348 // Adding assertions to a new dependency set at compile time:
349 void assert_evol_method(ciMethod* m);
350 void assert_leaf_type(ciKlass* ctxk);
351 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck);
352 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm);
353 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm, ciKlass* resolved_klass, ciMethod* resolved_method);
354 void assert_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk);
355 void assert_has_no_finalizable_subclasses(ciKlass* ctxk);
356 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle);
357 #if INCLUDE_JVMCI
358 private:
359 static void check_ctxk(Klass* ctxk) {
360 assert(ctxk->is_instance_klass(), "java types only");
361 }
362 static void check_ctxk_abstract(Klass* ctxk) {
363 check_ctxk(ctxk);
364 assert(ctxk->is_abstract(), "must be abstract");
365 }
366 static void check_unique_method(Klass* ctxk, Method* m) {
367 assert(!m->can_be_statically_bound(InstanceKlass::cast(ctxk)), "redundant");
368 }
369
370 void assert_common_1(DepType dept, DepValue x);
371 void assert_common_2(DepType dept, DepValue x0, DepValue x1);
372
373 public:
374 void assert_evol_method(Method* m);
375 void assert_has_no_finalizable_subclasses(Klass* ctxk);
376 void assert_leaf_type(Klass* ctxk);
377 void assert_unique_implementor(InstanceKlass* ctxk, InstanceKlass* uniqk);
378 void assert_unique_concrete_method(Klass* ctxk, Method* uniqm);
379 void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck);
380 void assert_call_site_target_value(oop callSite, oop methodHandle);
381 #endif // INCLUDE_JVMCI
382
383 // Define whether a given method or type is concrete.
384 // These methods define the term "concrete" as used in this module.
385 // For this module, an "abstract" class is one which is non-concrete.
386 //
387 // Future optimizations may allow some classes to remain
388 // non-concrete until their first instantiation, and allow some
389 // methods to remain non-concrete until their first invocation.
390 // In that case, there would be a middle ground between concrete
391 // and abstract (as defined by the Java language and VM).
392 static bool is_concrete_klass(Klass* k); // k is instantiable
393 static bool is_concrete_method(Method* m, Klass* k); // m is invocable
394 static Klass* find_finalizable_subclass(InstanceKlass* ik);
395
396 static bool is_concrete_root_method(Method* uniqm, InstanceKlass* ctxk);
397 static Klass* find_witness_AME(InstanceKlass* ctxk, Method* m, KlassDepChange* changes = nullptr);
398
399 // These versions of the concreteness queries work through the CI.
400 // The CI versions are allowed to skew sometimes from the VM
401 // (oop-based) versions. The cost of such a difference is a
402 // (safely) aborted compilation, or a deoptimization, or a missed
403 // optimization opportunity.
404 //
405 // In order to prevent spurious assertions, query results must
406 // remain stable within any single ciEnv instance. (I.e., they must
407 // not go back into the VM to get their value; they must cache the
408 // bit in the CI, either eagerly or lazily.)
409 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable
410 static bool has_finalizable_subclass(ciInstanceKlass* k);
411
412 // As a general rule, it is OK to compile under the assumption that
413 // a given type or method is concrete, even if it at some future
414 // point becomes abstract. So dependency checking is one-sided, in
415 // that it permits supposedly concrete classes or methods to turn up
416 // as really abstract. (This shouldn't happen, except during class
417 // evolution, but that's the logic of the checking.) However, if a
418 // supposedly abstract class or method suddenly becomes concrete, a
419 // dependency on it must fail.
420
421 // Checking old assertions at run-time (in the VM only):
422 static Klass* check_evol_method(Method* m);
423 static Klass* check_leaf_type(InstanceKlass* ctxk);
424 static Klass* check_abstract_with_unique_concrete_subtype(InstanceKlass* ctxk, Klass* conck, NewKlassDepChange* changes = nullptr);
425 static Klass* check_unique_implementor(InstanceKlass* ctxk, Klass* uniqk, NewKlassDepChange* changes = nullptr);
426 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, NewKlassDepChange* changes = nullptr);
427 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, Klass* resolved_klass, Method* resolved_method, KlassDepChange* changes = nullptr);
428 static Klass* check_has_no_finalizable_subclasses(InstanceKlass* ctxk, NewKlassDepChange* changes = nullptr);
429 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = nullptr);
430 // A returned Klass* is nullptr if the dependency assertion is still
431 // valid. A non-nullptr Klass* is a 'witness' to the assertion
432 // failure, a point in the class hierarchy where the assertion has
433 // been proven false. For example, if check_leaf_type returns
434 // non-nullptr, the value is a subtype of the supposed leaf type. This
435 // witness value may be useful for logging the dependency failure.
436 // Note that, when a dependency fails, there may be several possible
437 // witnesses to the failure. The value returned from the check_foo
438 // method is chosen arbitrarily.
439
440 // The 'changes' value, if non-null, requests a limited spot-check
441 // near the indicated recent changes in the class hierarchy.
442 // It is used by DepStream::spot_check_dependency_at.
443
444 // Detecting possible new assertions:
445 static Klass* find_unique_concrete_subtype(InstanceKlass* ctxk);
446 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m,
447 Klass** participant = nullptr); // out parameter
448 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m, Klass* resolved_klass, Method* resolved_method);
449
450 #ifdef ASSERT
451 static bool verify_method_context(InstanceKlass* ctxk, Method* m);
452 #endif // ASSERT
453
454 // Create the encoding which will be stored in an nmethod.
455 void encode_content_bytes();
456
457 address content_bytes() {
458 assert(_content_bytes != nullptr, "encode it first");
459 return _content_bytes;
460 }
461 size_t size_in_bytes() {
462 assert(_content_bytes != nullptr, "encode it first");
463 return _size_in_bytes;
464 }
465
466 OopRecorder* oop_recorder() { return _oop_recorder; }
467 CompileLog* log() { return _log; }
468
469 void copy_to(nmethod* nm);
470
471 static bool _verify_in_progress; // turn off logging dependencies
472
473 DepType validate_dependencies(CompileTask* task, char** failure_detail = nullptr);
474
475 void log_all_dependencies();
476
477 void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) {
478 ResourceMark rm;
479 int argslen = args->length();
480 write_dependency_to(log(), dept, args);
481 guarantee(argslen == args->length(),
482 "args array cannot grow inside nested ResoureMark scope");
483 }
484
485 void log_dependency(DepType dept,
486 ciBaseObject* x0,
487 ciBaseObject* x1 = nullptr,
488 ciBaseObject* x2 = nullptr,
489 ciBaseObject* x3 = nullptr) {
490 if (log() == nullptr) {
491 return;
492 }
493 ResourceMark rm;
494 GrowableArray<ciBaseObject*>* ciargs =
495 new GrowableArray<ciBaseObject*>(dep_args(dept));
496 assert (x0 != nullptr, "no log x0");
497 ciargs->push(x0);
498
499 if (x1 != nullptr) {
500 ciargs->push(x1);
501 }
502 if (x2 != nullptr) {
503 ciargs->push(x2);
504 }
505 if (x3 != nullptr) {
506 ciargs->push(x3);
507 }
508 assert(ciargs->length() == dep_args(dept), "");
509 log_dependency(dept, ciargs);
510 }
511
512 class DepArgument : public ResourceObj {
513 private:
514 bool _is_oop;
515 bool _valid;
516 void* _value;
517 public:
518 DepArgument() : _is_oop(false), _valid(false), _value(nullptr) {}
519 DepArgument(oop v): _is_oop(true), _valid(true), _value(v) {}
520 DepArgument(Metadata* v): _is_oop(false), _valid(true), _value(v) {}
521
522 bool is_null() const { return _value == nullptr; }
523 bool is_oop() const { return _is_oop; }
524 bool is_metadata() const { return !_is_oop; }
525 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); }
526 bool is_method() const { return is_metadata() && metadata_value()->is_method(); }
527
528 oop oop_value() const { assert(_is_oop && _valid, "must be"); return cast_to_oop(_value); }
529 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; }
530 };
531
532 static void print_dependency(DepType dept,
533 GrowableArray<DepArgument>* args,
534 Klass* witness = nullptr, outputStream* st = tty);
535
536 private:
537 // helper for encoding common context types as zero:
538 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x);
539
540 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x);
541
542 static void write_dependency_to(CompileLog* log,
543 DepType dept,
544 GrowableArray<ciBaseObject*>* args,
545 Klass* witness = nullptr);
546 static void write_dependency_to(CompileLog* log,
547 DepType dept,
548 GrowableArray<DepArgument>* args,
549 Klass* witness = nullptr);
550 static void write_dependency_to(xmlStream* xtty,
551 DepType dept,
552 GrowableArray<DepArgument>* args,
553 Klass* witness = nullptr);
554 public:
555 // Use this to iterate over an nmethod's dependency set.
556 // Works on new and old dependency sets.
557 // Usage:
558 //
559 // ;
560 // Dependencies::DepType dept;
561 // for (Dependencies::DepStream deps(nm); deps.next(); ) {
562 // ...
563 // }
564 //
565 // The caller must be in the VM, since oops are not wrapped in handles.
566 class DepStream {
567 private:
568 nmethod* _code; // null if in a compiler thread
569 Dependencies* _deps; // null if not in a compiler thread
570 CompressedReadStream _bytes;
571 #ifdef ASSERT
572 size_t _byte_limit;
573 #endif
574
575 // iteration variables:
576 DepType _type;
577 int _xi[max_arg_count+1];
578
579 void initial_asserts(size_t byte_limit) NOT_DEBUG({});
580
581 inline Metadata* recorded_metadata_at(int i);
582 inline oop recorded_oop_at(int i);
583
584 Klass* check_klass_dependency(KlassDepChange* changes);
585 Klass* check_new_klass_dependency(NewKlassDepChange* changes);
586 Klass* check_klass_init_dependency(KlassInitDepChange* changes);
587 Klass* check_call_site_dependency(CallSiteDepChange* changes);
588
589 void trace_and_log_witness(Klass* witness);
590
591 public:
592 DepStream(Dependencies* deps)
593 : _code(nullptr),
594 _deps(deps),
595 _bytes(deps->content_bytes())
596 {
597 initial_asserts(deps->size_in_bytes());
598 }
599 DepStream(nmethod* code)
600 : _code(code),
601 _deps(nullptr),
602 _bytes(code->dependencies_begin())
603 {
604 initial_asserts(code->dependencies_size());
605 }
606
607 bool next();
608
609 DepType type() { return _type; }
610 bool is_oop_argument(int i) { return type() == call_site_target_value; }
611 uintptr_t get_identifier(int i);
612
613 int argument_count() { return dep_args(type()); }
614 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob");
615 return _xi[i]; }
616 Metadata* argument(int i); // => recorded_oop_at(argument_index(i))
617 oop argument_oop(int i); // => recorded_oop_at(argument_index(i))
618 InstanceKlass* context_type();
619
620 bool is_klass_type() { return Dependencies::is_klass_type(type()); }
621
622 Method* method_argument(int i) {
623 Metadata* x = argument(i);
624 assert(x->is_method(), "type");
625 return (Method*) x;
626 }
627 Klass* type_argument(int i) {
628 Metadata* x = argument(i);
629 assert(x->is_klass(), "type");
630 return (Klass*) x;
631 }
632
633 // The point of the whole exercise: Is this dep still OK?
634 Klass* check_dependency() {
635 Klass* result = check_klass_dependency(nullptr);
636 if (result != nullptr) return result;
637 return check_call_site_dependency(nullptr);
638 }
639
640 // A lighter version: Checks only around recent changes in a class
641 // hierarchy. (See Universe::flush_dependents_on.)
642 Klass* spot_check_dependency_at(DepChange& changes);
643
644 // Log the current dependency to xtty or compilation log.
645 void log_dependency(Klass* witness = nullptr);
646
647 // Print the current dependency to tty.
648 void print_dependency(outputStream* st, Klass* witness = nullptr, bool verbose = false);
649 };
650 friend class Dependencies::DepStream;
651
652 static void print_statistics();
653 };
654
655
656 class DependencySignature : public ResourceObj {
657 private:
658 int _args_count;
659 uintptr_t _argument_hash[Dependencies::max_arg_count];
660 Dependencies::DepType _type;
661
662 public:
663 DependencySignature(Dependencies::DepStream& dep) {
664 _args_count = dep.argument_count();
665 _type = dep.type();
666 for (int i = 0; i < _args_count; i++) {
667 _argument_hash[i] = dep.get_identifier(i);
668 }
669 }
670
671 static bool equals(DependencySignature const& s1, DependencySignature const& s2);
672 static unsigned hash (DependencySignature const& s1) { return (unsigned)(s1.arg(0) >> 2); }
673
674 int args_count() const { return _args_count; }
675 uintptr_t arg(int idx) const { return _argument_hash[idx]; }
676 Dependencies::DepType type() const { return _type; }
677
678 };
679
680
681 // Every particular DepChange is a sub-class of this class.
682 class DepChange : public StackObj {
683 public:
684 // What kind of DepChange is this?
685 virtual bool is_klass_change() const { return false; }
686 virtual bool is_new_klass_change() const { return false; }
687 virtual bool is_klass_init_change() const { return false; }
688 virtual bool is_call_site_change() const { return false; }
689
690 // Subclass casting with assertions.
691 KlassDepChange* as_klass_change() {
692 assert(is_klass_change(), "bad cast");
693 return (KlassDepChange*) this;
694 }
695 NewKlassDepChange* as_new_klass_change() {
696 assert(is_new_klass_change(), "bad cast");
697 return (NewKlassDepChange*) this;
698 }
699 KlassInitDepChange* as_klass_init_change() {
700 assert(is_klass_init_change(), "bad cast");
701 return (KlassInitDepChange*) this;
702 }
703 CallSiteDepChange* as_call_site_change() {
704 assert(is_call_site_change(), "bad cast");
705 return (CallSiteDepChange*) this;
706 }
707
708 void print();
709 void print_on(outputStream* st);
710
711 public:
712 enum ChangeType {
713 NO_CHANGE = 0, // an uninvolved klass
714 Change_new_type, // a newly loaded type
715 Change_new_sub, // a super with a new subtype
716 Change_new_impl, // an interface with a new implementation
717 CHANGE_LIMIT,
718 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream
719 };
720
721 // Usage:
722 // for (DepChange::ContextStream str(changes); str.next(); ) {
723 // InstanceKlass* k = str.klass();
724 // switch (str.change_type()) {
725 // ...
726 // }
727 // }
728 class ContextStream : public StackObj {
729 private:
730 DepChange& _changes;
731 friend class DepChange;
732
733 // iteration variables:
734 ChangeType _change_type;
735 InstanceKlass* _klass;
736 Array<InstanceKlass*>* _ti_base; // i.e., transitive_interfaces
737 int _ti_index;
738 int _ti_limit;
739
740 // start at the beginning:
741 void start();
742
743 public:
744 ContextStream(DepChange& changes)
745 : _changes(changes)
746 { start(); }
747
748 ContextStream(DepChange& changes, NoSafepointVerifier& nsv)
749 : _changes(changes)
750 // the nsv argument makes it safe to hold oops like _klass
751 { start(); }
752
753 bool next();
754
755 ChangeType change_type() { return _change_type; }
756 InstanceKlass* klass() { return _klass; }
757 };
758 friend class DepChange::ContextStream;
759 };
760
761
762 // A class hierarchy change coming through the VM (under the Compile_lock).
763 // The change is structured as a single type with any number of supers
764 // and implemented interface types. Other than the type, any of the
765 // super types can be context types for a relevant dependency, which the
766 // type could invalidate.
767 class KlassDepChange : public DepChange {
768 private:
769 // each change set is rooted in exactly one type (at present):
770 InstanceKlass* _type;
771
772 void initialize();
773
774 protected:
775 // notes the type, marks it and all its super-types
776 KlassDepChange(InstanceKlass* type) : _type(type) {
777 initialize();
778 }
779
780 // cleans up the marks
781 ~KlassDepChange();
782
783 public:
784 // What kind of DepChange is this?
785 virtual bool is_klass_change() const { return true; }
786
787 InstanceKlass* type() { return _type; }
788
789 // involves_context(k) is true if k == _type or any of its super types
790 bool involves_context(Klass* k);
791 };
792
793 // A class hierarchy change: new type is loaded.
794 class NewKlassDepChange : public KlassDepChange {
795 public:
796 NewKlassDepChange(InstanceKlass* new_type) : KlassDepChange(new_type) {}
797
798 // What kind of DepChange is this?
799 virtual bool is_new_klass_change() const { return true; }
800
801 InstanceKlass* new_type() { return type(); }
802 };
803
804 // Change in initialization state of a loaded class.
805 class KlassInitDepChange : public KlassDepChange {
806 public:
807 KlassInitDepChange(InstanceKlass* type) : KlassDepChange(type) {}
808
809 // What kind of DepChange is this?
810 virtual bool is_klass_init_change() const { return true; }
811 };
812
813 // A CallSite has changed its target.
814 class CallSiteDepChange : public DepChange {
815 private:
816 Handle _call_site;
817 Handle _method_handle;
818
819 public:
820 CallSiteDepChange(Handle call_site, Handle method_handle);
821
822 // What kind of DepChange is this?
823 virtual bool is_call_site_change() const { return true; }
824
825 oop call_site() const { return _call_site(); }
826 oop method_handle() const { return _method_handle(); }
827 };
828
829 #endif // SHARE_CODE_DEPENDENCIES_HPP