1 /*
2 * Copyright (c) 2005, 2015, 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.
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20 * or visit www.oracle.com if you need additional information or have any
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23 */
24
25 #ifndef SHARE_VM_CODE_DEPENDENCIES_HPP
26 #define SHARE_VM_CODE_DEPENDENCIES_HPP
27
28 #include "ci/ciCallSite.hpp"
29 #include "ci/ciKlass.hpp"
30 #include "ci/ciMethodHandle.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "code/compressedStream.hpp"
33 #include "code/nmethod.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "utilities/growableArray.hpp"
36 #include "utilities/hashtable.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 DepChange;
60 class KlassDepChange;
61 class CallSiteDepChange;
62 class No_Safepoint_Verifier;
63
64 class Dependencies: public ResourceObj {
65 public:
66 // Note: In the comments on dependency types, most uses of the terms
67 // subtype and supertype are used in a "non-strict" or "inclusive"
68 // sense, and are starred to remind the reader of this fact.
69 // Strict uses of the terms use the word "proper".
70 //
71 // Specifically, every class is its own subtype* and supertype*.
72 // (This trick is easier than continually saying things like "Y is a
73 // subtype of X or X itself".)
74 //
75 // Sometimes we write X > Y to mean X is a proper supertype of Y.
76 // The notation X > {Y, Z} means X has proper subtypes Y, Z.
77 // The notation X.m > Y means that Y inherits m from X, while
78 // X.m > Y.m means Y overrides X.m. A star denotes abstractness,
79 // as *I > A, meaning (abstract) interface I is a super type of A,
80 // or A.*m > B.m, meaning B.m implements abstract method A.m.
81 //
82 // In this module, the terms "subtype" and "supertype" refer to
83 // Java-level reference type conversions, as detected by
84 // "instanceof" and performed by "checkcast" operations. The method
85 // Klass::is_subtype_of tests these relations. Note that "subtype"
86 // is richer than "subclass" (as tested by Klass::is_subclass_of),
87 // since it takes account of relations involving interface and array
88 // types.
89 //
90 // To avoid needless complexity, dependencies involving array types
91 // are not accepted. If you need to make an assertion about an
92 // array type, make the assertion about its corresponding element
93 // types. Any assertion that might change about an array type can
94 // be converted to an assertion about its element type.
95 //
96 // Most dependencies are evaluated over a "context type" CX, which
97 // stands for the set Subtypes(CX) of every Java type that is a subtype*
98 // of CX. When the system loads a new class or interface N, it is
99 // responsible for re-evaluating changed dependencies whose context
100 // type now includes N, that is, all super types of N.
101 //
102 enum DepType {
103 end_marker = 0,
104
105 // An 'evol' dependency simply notes that the contents of the
106 // method were used. If it evolves (is replaced), the nmethod
107 // must be recompiled. No other dependencies are implied.
108 evol_method,
109 FIRST_TYPE = evol_method,
110
111 // A context type CX is a leaf it if has no proper subtype.
112 leaf_type,
113
114 // An abstract class CX has exactly one concrete subtype CC.
115 abstract_with_unique_concrete_subtype,
116
117 // The type CX is purely abstract, with no concrete subtype* at all.
118 abstract_with_no_concrete_subtype,
119
120 // The concrete CX is free of concrete proper subtypes.
121 concrete_with_no_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, // one unique concrete method under CX
140
141 // An "exclusive" assertion concerns two methods or subtypes, and
142 // declares that there are at most two (or perhaps later N>2)
143 // specific items that jointly satisfy the restriction.
144 // We list all items explicitly rather than just giving their
145 // count, for robustness in the face of complex schema changes.
146
147 // A context class CX (which may be either abstract or concrete)
148 // has two exclusive concrete subtypes* C1, C2 if every concrete
149 // subtype* of CX is either C1 or C2. Note that if neither C1 or C2
150 // are equal to CX, then CX itself must be abstract. But it is
151 // also possible (for example) that C1 is CX (a concrete class)
152 // and C2 is a proper subtype of C1.
153 abstract_with_exclusive_concrete_subtypes_2,
154
155 // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}.
156 exclusive_concrete_methods_2,
157
158 // This dependency asserts that no instances of class or it's
159 // subclasses require finalization registration.
160 no_finalizable_subclasses,
161
162 // This dependency asserts when the CallSite.target value changed.
163 call_site_target_value,
164
165 TYPE_LIMIT
166 };
167 enum {
168 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
169
170 // handy categorizations of dependency types:
171 all_types = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE),
172
173 non_klass_types = (1 << call_site_target_value),
174 klass_types = all_types & ~non_klass_types,
175
176 non_ctxk_types = (1 << evol_method) | (1 << call_site_target_value),
177 implicit_ctxk_types = 0,
178 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
179
180 max_arg_count = 3, // current maximum number of arguments (incl. ctxk)
181
182 // A "context type" is a class or interface that
183 // provides context for evaluating a dependency.
184 // When present, it is one of the arguments (dep_context_arg).
185 //
186 // If a dependency does not have a context type, there is a
187 // default context, depending on the type of the dependency.
188 // This bit signals that a default context has been compressed away.
189 default_context_type_bit = (1<<LG2_TYPE_LIMIT)
190 };
191
192 static const char* dep_name(DepType dept);
193 static int dep_args(DepType dept);
194
195 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); }
196
197 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); }
198 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); }
199
200 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; }
201 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; }
202
203 static void check_valid_dependency_type(DepType dept);
204
205 #if INCLUDE_JVMCI
206 // A Metadata* or object value recorded in an OopRecorder
207 class DepValue VALUE_OBJ_CLASS_SPEC {
208 private:
209 // Unique identifier of the value within the associated OopRecorder that
210 // encodes both the category of the value (0: invalid, positive: metadata, negative: object)
211 // and the index within a category specific array (metadata: index + 1, object: -(index + 1))
212 int _id;
213
214 public:
215 DepValue() : _id(0) {}
216 DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = NULL) {
217 assert(candidate == NULL || candidate->is_metadata(), "oops");
218 if (candidate != NULL && candidate->as_metadata(rec) == metadata) {
219 _id = candidate->_id;
220 } else {
221 _id = rec->find_index(metadata) + 1;
222 }
223 }
224 DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = NULL) {
225 assert(candidate == NULL || candidate->is_object(), "oops");
226 if (candidate != NULL && candidate->as_object(rec) == obj) {
227 _id = candidate->_id;
228 } else {
229 _id = -(rec->find_index(obj) + 1);
230 }
231 }
232
233 // Used to sort values in ascending order of index() with metadata values preceding object values
234 int sort_key() const { return -_id; }
235
236 bool operator == (const DepValue& other) const { return other._id == _id; }
237
238 bool is_valid() const { return _id != 0; }
239 int index() const { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; }
240 bool is_metadata() const { assert(is_valid(), "oops"); return _id > 0; }
241 bool is_object() const { assert(is_valid(), "oops"); return _id < 0; }
242
243 Metadata* as_metadata(OopRecorder* rec) const { assert(is_metadata(), "oops"); return rec->metadata_at(index()); }
244 Klass* as_klass(OopRecorder* rec) const { assert(as_metadata(rec)->is_klass(), "oops"); return (Klass*) as_metadata(rec); }
245 Method* as_method(OopRecorder* rec) const { assert(as_metadata(rec)->is_method(), "oops"); return (Method*) as_metadata(rec); }
246 jobject as_object(OopRecorder* rec) const { assert(is_object(), "oops"); return rec->oop_at(index()); }
247 };
248 #endif
249
250 private:
251 // State for writing a new set of dependencies:
252 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept))
253 GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT];
254 #if INCLUDE_JVMCI
255 bool _using_dep_values;
256 GrowableArray<DepValue>* _dep_values[TYPE_LIMIT];
257 #endif
258
259 static const char* _dep_name[TYPE_LIMIT];
260 static int _dep_args[TYPE_LIMIT];
261
262 static bool dept_in_mask(DepType dept, int mask) {
263 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0;
264 }
265
266 bool note_dep_seen(int dept, ciBaseObject* x) {
267 assert(dept < BitsPerInt, "oob");
268 int x_id = x->ident();
269 assert(_dep_seen != NULL, "deps must be writable");
270 int seen = _dep_seen->at_grow(x_id, 0);
271 _dep_seen->at_put(x_id, seen | (1<<dept));
272 // return true if we've already seen dept/x
273 return (seen & (1<<dept)) != 0;
274 }
275
276 #if INCLUDE_JVMCI
277 bool note_dep_seen(int dept, DepValue x) {
278 assert(dept < BitsPerInt, "oops");
279 // place metadata deps at even indexes, object deps at odd indexes
280 int x_id = x.is_metadata() ? x.index() * 2 : (x.index() * 2) + 1;
281 assert(_dep_seen != NULL, "deps must be writable");
282 int seen = _dep_seen->at_grow(x_id, 0);
283 _dep_seen->at_put(x_id, seen | (1<<dept));
284 // return true if we've already seen dept/x
285 return (seen & (1<<dept)) != 0;
286 }
287 #endif
288
289 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
290 int ctxk_i, ciKlass* ctxk);
291 #if INCLUDE_JVMCI
292 bool maybe_merge_ctxk(GrowableArray<DepValue>* deps,
293 int ctxk_i, DepValue ctxk);
294 #endif
295
296 void sort_all_deps();
297 size_t estimate_size_in_bytes();
298
299 // Initialize _deps, etc.
300 void initialize(ciEnv* env);
301
302 // State for making a new set of dependencies:
303 OopRecorder* _oop_recorder;
304
305 // Logging support
306 CompileLog* _log;
307
308 address _content_bytes; // everything but the oop references, encoded
309 size_t _size_in_bytes;
310
311 public:
312 // Make a new empty dependencies set.
313 Dependencies(ciEnv* env) {
314 initialize(env);
315 }
316 #if INCLUDE_JVMCI
317 Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log);
318 #endif
319
320 private:
321 // Check for a valid context type.
322 // Enforce the restriction against array types.
323 static void check_ctxk(ciKlass* ctxk) {
324 assert(ctxk->is_instance_klass(), "java types only");
325 }
326 static void check_ctxk_concrete(ciKlass* ctxk) {
327 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete");
328 }
329 static void check_ctxk_abstract(ciKlass* ctxk) {
330 check_ctxk(ctxk);
331 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract");
332 }
333
334 void assert_common_1(DepType dept, ciBaseObject* x);
335 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1);
336 void assert_common_3(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2);
337
338 public:
339 // Adding assertions to a new dependency set at compile time:
340 void assert_evol_method(ciMethod* m);
341 void assert_leaf_type(ciKlass* ctxk);
342 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck);
343 void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk);
344 void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk);
345 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm);
346 void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2);
347 void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2);
348 void assert_has_no_finalizable_subclasses(ciKlass* ctxk);
349 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle);
350
351 #if INCLUDE_JVMCI
352 private:
353 static void check_ctxk(Klass* ctxk) {
354 assert(ctxk->oop_is_instance(), "java types only");
355 }
356 static void check_ctxk_abstract(Klass* ctxk) {
357 check_ctxk(ctxk);
358 assert(ctxk->is_abstract(), "must be abstract");
359 }
360 void assert_common_1(DepType dept, DepValue x);
361 void assert_common_2(DepType dept, DepValue x0, DepValue x1);
362
363 public:
364 void assert_evol_method(Method* m);
365 void assert_has_no_finalizable_subclasses(Klass* ctxk);
366 void assert_leaf_type(Klass* ctxk);
367 void assert_unique_concrete_method(Klass* ctxk, Method* uniqm);
368 void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck);
369 void assert_call_site_target_value(oop callSite, oop methodHandle);
370 #endif // JVMCI
371
372 // Define whether a given method or type is concrete.
373 // These methods define the term "concrete" as used in this module.
374 // For this module, an "abstract" class is one which is non-concrete.
375 //
376 // Future optimizations may allow some classes to remain
377 // non-concrete until their first instantiation, and allow some
378 // methods to remain non-concrete until their first invocation.
379 // In that case, there would be a middle ground between concrete
380 // and abstract (as defined by the Java language and VM).
381 static bool is_concrete_klass(Klass* k); // k is instantiable
382 static bool is_concrete_method(Method* m, Klass* k); // m is invocable
383 static Klass* find_finalizable_subclass(Klass* k);
384
385 // These versions of the concreteness queries work through the CI.
386 // The CI versions are allowed to skew sometimes from the VM
387 // (oop-based) versions. The cost of such a difference is a
388 // (safely) aborted compilation, or a deoptimization, or a missed
389 // optimization opportunity.
390 //
391 // In order to prevent spurious assertions, query results must
392 // remain stable within any single ciEnv instance. (I.e., they must
393 // not go back into the VM to get their value; they must cache the
394 // bit in the CI, either eagerly or lazily.)
395 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable
396 static bool has_finalizable_subclass(ciInstanceKlass* k);
397
398 // As a general rule, it is OK to compile under the assumption that
399 // a given type or method is concrete, even if it at some future
400 // point becomes abstract. So dependency checking is one-sided, in
401 // that it permits supposedly concrete classes or methods to turn up
402 // as really abstract. (This shouldn't happen, except during class
403 // evolution, but that's the logic of the checking.) However, if a
404 // supposedly abstract class or method suddenly becomes concrete, a
405 // dependency on it must fail.
406
407 // Checking old assertions at run-time (in the VM only):
408 static Klass* check_evol_method(Method* m);
409 static Klass* check_leaf_type(Klass* ctxk);
410 static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck,
411 KlassDepChange* changes = NULL);
412 static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk,
413 KlassDepChange* changes = NULL);
414 static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk,
415 KlassDepChange* changes = NULL);
416 static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm,
417 KlassDepChange* changes = NULL);
418 static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2,
419 KlassDepChange* changes = NULL);
420 static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2,
421 KlassDepChange* changes = NULL);
422 static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL);
423 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
424 // A returned Klass* is NULL if the dependency assertion is still
425 // valid. A non-NULL Klass* is a 'witness' to the assertion
426 // failure, a point in the class hierarchy where the assertion has
427 // been proven false. For example, if check_leaf_type returns
428 // non-NULL, the value is a subtype of the supposed leaf type. This
429 // witness value may be useful for logging the dependency failure.
430 // Note that, when a dependency fails, there may be several possible
431 // witnesses to the failure. The value returned from the check_foo
432 // method is chosen arbitrarily.
433
434 // The 'changes' value, if non-null, requests a limited spot-check
435 // near the indicated recent changes in the class hierarchy.
436 // It is used by DepStream::spot_check_dependency_at.
437
438 // Detecting possible new assertions:
439 static Klass* find_unique_concrete_subtype(Klass* ctxk);
440 static Method* find_unique_concrete_method(Klass* ctxk, Method* m);
441 static int find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]);
442
443 // Create the encoding which will be stored in an nmethod.
444 void encode_content_bytes();
445
446 address content_bytes() {
447 assert(_content_bytes != NULL, "encode it first");
448 return _content_bytes;
449 }
450 size_t size_in_bytes() {
451 assert(_content_bytes != NULL, "encode it first");
452 return _size_in_bytes;
453 }
454
455 OopRecorder* oop_recorder() { return _oop_recorder; }
456 CompileLog* log() { return _log; }
457
458 void copy_to(nmethod* nm);
459
460 void log_all_dependencies();
461
462 void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) {
463 ResourceMark rm;
464 int argslen = args->length();
465 write_dependency_to(log(), dept, args);
466 guarantee(argslen == args->length(),
467 "args array cannot grow inside nested ResoureMark scope");
468 }
469
470 void log_dependency(DepType dept,
471 ciBaseObject* x0,
472 ciBaseObject* x1 = NULL,
473 ciBaseObject* x2 = NULL) {
474 if (log() == NULL) {
475 return;
476 }
477 ResourceMark rm;
478 GrowableArray<ciBaseObject*>* ciargs =
479 new GrowableArray<ciBaseObject*>(dep_args(dept));
480 assert (x0 != NULL, "no log x0");
481 ciargs->push(x0);
482
483 if (x1 != NULL) {
484 ciargs->push(x1);
485 }
486 if (x2 != NULL) {
487 ciargs->push(x2);
488 }
489 assert(ciargs->length() == dep_args(dept), "");
490 log_dependency(dept, ciargs);
491 }
492
493 class DepArgument : public ResourceObj {
494 private:
495 bool _is_oop;
496 bool _valid;
497 void* _value;
498 public:
499 DepArgument() : _is_oop(false), _value(NULL), _valid(false) {}
500 DepArgument(oop v): _is_oop(true), _value(v), _valid(true) {}
501 DepArgument(Metadata* v): _is_oop(false), _value(v), _valid(true) {}
502
503 bool is_null() const { return _value == NULL; }
504 bool is_oop() const { return _is_oop; }
505 bool is_metadata() const { return !_is_oop; }
506 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); }
507 bool is_method() const { return is_metadata() && metadata_value()->is_method(); }
508
509 oop oop_value() const { assert(_is_oop && _valid, "must be"); return (oop) _value; }
510 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; }
511 };
512
513 static void print_dependency(DepType dept,
514 GrowableArray<DepArgument>* args,
515 Klass* witness = NULL, outputStream* st = tty);
516
517 private:
518 // helper for encoding common context types as zero:
519 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x);
520
521 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x);
522
523 static void write_dependency_to(CompileLog* log,
524 DepType dept,
525 GrowableArray<ciBaseObject*>* args,
526 Klass* witness = NULL);
527 static void write_dependency_to(CompileLog* log,
528 DepType dept,
529 GrowableArray<DepArgument>* args,
530 Klass* witness = NULL);
531 static void write_dependency_to(xmlStream* xtty,
532 DepType dept,
533 GrowableArray<DepArgument>* args,
534 Klass* witness = NULL);
535 public:
536 // Use this to iterate over an nmethod's dependency set.
537 // Works on new and old dependency sets.
538 // Usage:
539 //
540 // ;
541 // Dependencies::DepType dept;
542 // for (Dependencies::DepStream deps(nm); deps.next(); ) {
543 // ...
544 // }
545 //
546 // The caller must be in the VM, since oops are not wrapped in handles.
547 class DepStream {
548 private:
549 nmethod* _code; // null if in a compiler thread
550 Dependencies* _deps; // null if not in a compiler thread
551 CompressedReadStream _bytes;
552 #ifdef ASSERT
553 size_t _byte_limit;
554 #endif
555
556 // iteration variables:
557 DepType _type;
558 int _xi[max_arg_count+1];
559
560 void initial_asserts(size_t byte_limit) NOT_DEBUG({});
561
562 inline Metadata* recorded_metadata_at(int i);
563 inline oop recorded_oop_at(int i);
564
565 Klass* check_klass_dependency(KlassDepChange* changes);
566 Klass* check_call_site_dependency(CallSiteDepChange* changes);
567
568 void trace_and_log_witness(Klass* witness);
569
570 public:
571 DepStream(Dependencies* deps)
572 : _deps(deps),
573 _code(NULL),
574 _bytes(deps->content_bytes())
575 {
576 initial_asserts(deps->size_in_bytes());
577 }
578 DepStream(nmethod* code)
579 : _deps(NULL),
580 _code(code),
581 _bytes(code->dependencies_begin())
582 {
583 initial_asserts(code->dependencies_size());
584 }
585
586 bool next();
587
588 DepType type() { return _type; }
589 bool is_oop_argument(int i) { return type() == call_site_target_value; }
590 uintptr_t get_identifier(int i);
591
592 int argument_count() { return dep_args(type()); }
593 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob");
594 return _xi[i]; }
595 Metadata* argument(int i); // => recorded_oop_at(argument_index(i))
596 oop argument_oop(int i); // => recorded_oop_at(argument_index(i))
597 Klass* context_type();
598
599 bool is_klass_type() { return Dependencies::is_klass_type(type()); }
600
601 Method* method_argument(int i) {
602 Metadata* x = argument(i);
603 assert(x->is_method(), "type");
604 return (Method*) x;
605 }
606 Klass* type_argument(int i) {
607 Metadata* x = argument(i);
608 assert(x->is_klass(), "type");
609 return (Klass*) x;
610 }
611
612 // The point of the whole exercise: Is this dep still OK?
613 Klass* check_dependency() {
614 Klass* result = check_klass_dependency(NULL);
615 if (result != NULL) return result;
616 return check_call_site_dependency(NULL);
617 }
618
619 // A lighter version: Checks only around recent changes in a class
620 // hierarchy. (See Universe::flush_dependents_on.)
621 Klass* spot_check_dependency_at(DepChange& changes);
622
623 // Log the current dependency to xtty or compilation log.
624 void log_dependency(Klass* witness = NULL);
625
626 // Print the current dependency to tty.
627 void print_dependency(Klass* witness = NULL, bool verbose = false, outputStream* st = tty);
628 };
629 friend class Dependencies::DepStream;
630
631 static void print_statistics() PRODUCT_RETURN;
632 };
633
634
635 class DependencySignature : public ResourceObj {
636 private:
637 int _args_count;
638 uintptr_t _argument_hash[Dependencies::max_arg_count];
639 Dependencies::DepType _type;
640
641 public:
642 DependencySignature(Dependencies::DepStream& dep) {
643 _args_count = dep.argument_count();
644 _type = dep.type();
645 for (int i = 0; i < _args_count; i++) {
646 _argument_hash[i] = dep.get_identifier(i);
647 }
648 }
649
650 static bool equals(DependencySignature const& s1, DependencySignature const& s2);
651 static unsigned hash (DependencySignature const& s1) { return s1.arg(0) >> 2; }
652
653 int args_count() const { return _args_count; }
654 uintptr_t arg(int idx) const { return _argument_hash[idx]; }
655 Dependencies::DepType type() const { return _type; }
656
657 };
658
659
660 // Every particular DepChange is a sub-class of this class.
661 class DepChange : public StackObj {
662 public:
663 // What kind of DepChange is this?
664 virtual bool is_klass_change() const { return false; }
665 virtual bool is_call_site_change() const { return false; }
666
667 // Subclass casting with assertions.
668 KlassDepChange* as_klass_change() {
669 assert(is_klass_change(), "bad cast");
670 return (KlassDepChange*) this;
671 }
672 CallSiteDepChange* as_call_site_change() {
673 assert(is_call_site_change(), "bad cast");
674 return (CallSiteDepChange*) this;
675 }
676
677 void print();
678
679 public:
680 enum ChangeType {
681 NO_CHANGE = 0, // an uninvolved klass
682 Change_new_type, // a newly loaded type
683 Change_new_sub, // a super with a new subtype
684 Change_new_impl, // an interface with a new implementation
685 CHANGE_LIMIT,
686 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream
687 };
688
689 // Usage:
690 // for (DepChange::ContextStream str(changes); str.next(); ) {
691 // Klass* k = str.klass();
692 // switch (str.change_type()) {
693 // ...
694 // }
695 // }
696 class ContextStream : public StackObj {
697 private:
698 DepChange& _changes;
699 friend class DepChange;
700
701 // iteration variables:
702 ChangeType _change_type;
703 Klass* _klass;
704 Array<Klass*>* _ti_base; // i.e., transitive_interfaces
705 int _ti_index;
706 int _ti_limit;
707
708 // start at the beginning:
709 void start();
710
711 public:
712 ContextStream(DepChange& changes)
713 : _changes(changes)
714 { start(); }
715
716 ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv)
717 : _changes(changes)
718 // the nsv argument makes it safe to hold oops like _klass
719 { start(); }
720
721 bool next();
722
723 ChangeType change_type() { return _change_type; }
724 Klass* klass() { return _klass; }
725 };
726 friend class DepChange::ContextStream;
727 };
728
729
730 // A class hierarchy change coming through the VM (under the Compile_lock).
731 // The change is structured as a single new type with any number of supers
732 // and implemented interface types. Other than the new type, any of the
733 // super types can be context types for a relevant dependency, which the
734 // new type could invalidate.
735 class KlassDepChange : public DepChange {
736 private:
737 // each change set is rooted in exactly one new type (at present):
738 KlassHandle _new_type;
739
740 void initialize();
741
742 public:
743 // notes the new type, marks it and all its super-types
744 KlassDepChange(KlassHandle new_type)
745 : _new_type(new_type)
746 {
747 initialize();
748 }
749
750 // cleans up the marks
751 ~KlassDepChange();
752
753 // What kind of DepChange is this?
754 virtual bool is_klass_change() const { return true; }
755
756 Klass* new_type() { return _new_type(); }
757
758 // involves_context(k) is true if k is new_type or any of the super types
759 bool involves_context(Klass* k);
760 };
761
762
763 // A CallSite has changed its target.
764 class CallSiteDepChange : public DepChange {
765 private:
766 Handle _call_site;
767 Handle _method_handle;
768
769 public:
770 CallSiteDepChange(Handle call_site, Handle method_handle)
771 : _call_site(call_site),
772 _method_handle(method_handle)
773 {
774 assert(_call_site() ->is_a(SystemDictionary::CallSite_klass()), "must be");
775 assert(_method_handle.is_null() || _method_handle()->is_a(SystemDictionary::MethodHandle_klass()), "must be");
776 }
777
778 // What kind of DepChange is this?
779 virtual bool is_call_site_change() const { return true; }
780
781 oop call_site() const { return _call_site(); }
782 oop method_handle() const { return _method_handle(); }
783 };
784
785 #endif // SHARE_VM_CODE_DEPENDENCIES_HPP