Wed, 31 Jan 2018 19:24:57 -0500
8189170: Add option to disable stack overflow checking in primordial thread for use with JNI_CreateJavaJVM
Reviewed-by: dcubed
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_CODE_DEPENDENCIES_HPP
26 #define SHARE_VM_CODE_DEPENDENCIES_HPP
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 "utilities/growableArray.hpp"
36 //** Dependencies represent assertions (approximate invariants) within
37 // the runtime system, e.g. class hierarchy changes. An example is an
38 // assertion that a given method is not overridden; another example is
39 // that a type has only one concrete subtype. Compiled code which
40 // relies on such assertions must be discarded if they are overturned
41 // by changes in the runtime system. We can think of these assertions
42 // as approximate invariants, because we expect them to be overturned
43 // very infrequently. We are willing to perform expensive recovery
44 // operations when they are overturned. The benefit, of course, is
45 // performing optimistic optimizations (!) on the object code.
46 //
47 // Changes in the class hierarchy due to dynamic linking or
48 // class evolution can violate dependencies. There is enough
49 // indexing between classes and nmethods to make dependency
50 // checking reasonably efficient.
52 class ciEnv;
53 class nmethod;
54 class OopRecorder;
55 class xmlStream;
56 class CompileLog;
57 class DepChange;
58 class KlassDepChange;
59 class CallSiteDepChange;
60 class No_Safepoint_Verifier;
62 class Dependencies: public ResourceObj {
63 public:
64 // Note: In the comments on dependency types, most uses of the terms
65 // subtype and supertype are used in a "non-strict" or "inclusive"
66 // sense, and are starred to remind the reader of this fact.
67 // Strict uses of the terms use the word "proper".
68 //
69 // Specifically, every class is its own subtype* and supertype*.
70 // (This trick is easier than continually saying things like "Y is a
71 // subtype of X or X itself".)
72 //
73 // Sometimes we write X > Y to mean X is a proper supertype of Y.
74 // The notation X > {Y, Z} means X has proper subtypes Y, Z.
75 // The notation X.m > Y means that Y inherits m from X, while
76 // X.m > Y.m means Y overrides X.m. A star denotes abstractness,
77 // as *I > A, meaning (abstract) interface I is a super type of A,
78 // or A.*m > B.m, meaning B.m implements abstract method A.m.
79 //
80 // In this module, the terms "subtype" and "supertype" refer to
81 // Java-level reference type conversions, as detected by
82 // "instanceof" and performed by "checkcast" operations. The method
83 // Klass::is_subtype_of tests these relations. Note that "subtype"
84 // is richer than "subclass" (as tested by Klass::is_subclass_of),
85 // since it takes account of relations involving interface and array
86 // types.
87 //
88 // To avoid needless complexity, dependencies involving array types
89 // are not accepted. If you need to make an assertion about an
90 // array type, make the assertion about its corresponding element
91 // types. Any assertion that might change about an array type can
92 // be converted to an assertion about its element type.
93 //
94 // Most dependencies are evaluated over a "context type" CX, which
95 // stands for the set Subtypes(CX) of every Java type that is a subtype*
96 // of CX. When the system loads a new class or interface N, it is
97 // responsible for re-evaluating changed dependencies whose context
98 // type now includes N, that is, all super types of N.
99 //
100 enum DepType {
101 end_marker = 0,
103 // An 'evol' dependency simply notes that the contents of the
104 // method were used. If it evolves (is replaced), the nmethod
105 // must be recompiled. No other dependencies are implied.
106 evol_method,
107 FIRST_TYPE = evol_method,
109 // A context type CX is a leaf it if has no proper subtype.
110 leaf_type,
112 // An abstract class CX has exactly one concrete subtype CC.
113 abstract_with_unique_concrete_subtype,
115 // The type CX is purely abstract, with no concrete subtype* at all.
116 abstract_with_no_concrete_subtype,
118 // The concrete CX is free of concrete proper subtypes.
119 concrete_with_no_concrete_subtype,
121 // Given a method M1 and a context class CX, the set MM(CX, M1) of
122 // "concrete matching methods" in CX of M1 is the set of every
123 // concrete M2 for which it is possible to create an invokevirtual
124 // or invokeinterface call site that can reach either M1 or M2.
125 // That is, M1 and M2 share a name, signature, and vtable index.
126 // We wish to notice when the set MM(CX, M1) is just {M1}, or
127 // perhaps a set of two {M1,M2}, and issue dependencies on this.
129 // The set MM(CX, M1) can be computed by starting with any matching
130 // concrete M2 that is inherited into CX, and then walking the
131 // subtypes* of CX looking for concrete definitions.
133 // The parameters to this dependency are the method M1 and the
134 // context class CX. M1 must be either inherited in CX or defined
135 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater
136 // than {M1}.
137 unique_concrete_method, // one unique concrete method under CX
139 // An "exclusive" assertion concerns two methods or subtypes, and
140 // declares that there are at most two (or perhaps later N>2)
141 // specific items that jointly satisfy the restriction.
142 // We list all items explicitly rather than just giving their
143 // count, for robustness in the face of complex schema changes.
145 // A context class CX (which may be either abstract or concrete)
146 // has two exclusive concrete subtypes* C1, C2 if every concrete
147 // subtype* of CX is either C1 or C2. Note that if neither C1 or C2
148 // are equal to CX, then CX itself must be abstract. But it is
149 // also possible (for example) that C1 is CX (a concrete class)
150 // and C2 is a proper subtype of C1.
151 abstract_with_exclusive_concrete_subtypes_2,
153 // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}.
154 exclusive_concrete_methods_2,
156 // This dependency asserts that no instances of class or it's
157 // subclasses require finalization registration.
158 no_finalizable_subclasses,
160 // This dependency asserts when the CallSite.target value changed.
161 call_site_target_value,
163 TYPE_LIMIT
164 };
165 enum {
166 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
168 // handy categorizations of dependency types:
169 all_types = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE),
171 non_klass_types = (1 << call_site_target_value),
172 klass_types = all_types & ~non_klass_types,
174 non_ctxk_types = (1 << evol_method),
175 implicit_ctxk_types = (1 << call_site_target_value),
176 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
178 max_arg_count = 3, // current maximum number of arguments (incl. ctxk)
180 // A "context type" is a class or interface that
181 // provides context for evaluating a dependency.
182 // When present, it is one of the arguments (dep_context_arg).
183 //
184 // If a dependency does not have a context type, there is a
185 // default context, depending on the type of the dependency.
186 // This bit signals that a default context has been compressed away.
187 default_context_type_bit = (1<<LG2_TYPE_LIMIT)
188 };
190 static const char* dep_name(DepType dept);
191 static int dep_args(DepType dept);
193 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); }
195 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); }
196 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); }
198 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; }
199 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; }
201 static void check_valid_dependency_type(DepType dept);
203 private:
204 // State for writing a new set of dependencies:
205 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept))
206 GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT];
208 static const char* _dep_name[TYPE_LIMIT];
209 static int _dep_args[TYPE_LIMIT];
211 static bool dept_in_mask(DepType dept, int mask) {
212 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0;
213 }
215 bool note_dep_seen(int dept, ciBaseObject* x) {
216 assert(dept < BitsPerInt, "oob");
217 int x_id = x->ident();
218 assert(_dep_seen != NULL, "deps must be writable");
219 int seen = _dep_seen->at_grow(x_id, 0);
220 _dep_seen->at_put(x_id, seen | (1<<dept));
221 // return true if we've already seen dept/x
222 return (seen & (1<<dept)) != 0;
223 }
225 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
226 int ctxk_i, ciKlass* ctxk);
228 void sort_all_deps();
229 size_t estimate_size_in_bytes();
231 // Initialize _deps, etc.
232 void initialize(ciEnv* env);
234 // State for making a new set of dependencies:
235 OopRecorder* _oop_recorder;
237 // Logging support
238 CompileLog* _log;
240 address _content_bytes; // everything but the oop references, encoded
241 size_t _size_in_bytes;
243 public:
244 // Make a new empty dependencies set.
245 Dependencies(ciEnv* env) {
246 initialize(env);
247 }
249 private:
250 // Check for a valid context type.
251 // Enforce the restriction against array types.
252 static void check_ctxk(ciKlass* ctxk) {
253 assert(ctxk->is_instance_klass(), "java types only");
254 }
255 static void check_ctxk_concrete(ciKlass* ctxk) {
256 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete");
257 }
258 static void check_ctxk_abstract(ciKlass* ctxk) {
259 check_ctxk(ctxk);
260 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract");
261 }
263 void assert_common_1(DepType dept, ciBaseObject* x);
264 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1);
265 void assert_common_3(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2);
267 public:
268 // Adding assertions to a new dependency set at compile time:
269 void assert_evol_method(ciMethod* m);
270 void assert_leaf_type(ciKlass* ctxk);
271 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck);
272 void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk);
273 void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk);
274 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm);
275 void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2);
276 void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2);
277 void assert_has_no_finalizable_subclasses(ciKlass* ctxk);
278 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle);
280 // Define whether a given method or type is concrete.
281 // These methods define the term "concrete" as used in this module.
282 // For this module, an "abstract" class is one which is non-concrete.
283 //
284 // Future optimizations may allow some classes to remain
285 // non-concrete until their first instantiation, and allow some
286 // methods to remain non-concrete until their first invocation.
287 // In that case, there would be a middle ground between concrete
288 // and abstract (as defined by the Java language and VM).
289 static bool is_concrete_klass(Klass* k); // k is instantiable
290 static bool is_concrete_method(Method* m, Klass* k); // m is invocable
291 static Klass* find_finalizable_subclass(Klass* k);
293 // These versions of the concreteness queries work through the CI.
294 // The CI versions are allowed to skew sometimes from the VM
295 // (oop-based) versions. The cost of such a difference is a
296 // (safely) aborted compilation, or a deoptimization, or a missed
297 // optimization opportunity.
298 //
299 // In order to prevent spurious assertions, query results must
300 // remain stable within any single ciEnv instance. (I.e., they must
301 // not go back into the VM to get their value; they must cache the
302 // bit in the CI, either eagerly or lazily.)
303 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable
304 static bool has_finalizable_subclass(ciInstanceKlass* k);
306 // As a general rule, it is OK to compile under the assumption that
307 // a given type or method is concrete, even if it at some future
308 // point becomes abstract. So dependency checking is one-sided, in
309 // that it permits supposedly concrete classes or methods to turn up
310 // as really abstract. (This shouldn't happen, except during class
311 // evolution, but that's the logic of the checking.) However, if a
312 // supposedly abstract class or method suddenly becomes concrete, a
313 // dependency on it must fail.
315 // Checking old assertions at run-time (in the VM only):
316 static Klass* check_evol_method(Method* m);
317 static Klass* check_leaf_type(Klass* ctxk);
318 static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck,
319 KlassDepChange* changes = NULL);
320 static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk,
321 KlassDepChange* changes = NULL);
322 static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk,
323 KlassDepChange* changes = NULL);
324 static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm,
325 KlassDepChange* changes = NULL);
326 static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2,
327 KlassDepChange* changes = NULL);
328 static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2,
329 KlassDepChange* changes = NULL);
330 static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL);
331 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
332 // A returned Klass* is NULL if the dependency assertion is still
333 // valid. A non-NULL Klass* is a 'witness' to the assertion
334 // failure, a point in the class hierarchy where the assertion has
335 // been proven false. For example, if check_leaf_type returns
336 // non-NULL, the value is a subtype of the supposed leaf type. This
337 // witness value may be useful for logging the dependency failure.
338 // Note that, when a dependency fails, there may be several possible
339 // witnesses to the failure. The value returned from the check_foo
340 // method is chosen arbitrarily.
342 // The 'changes' value, if non-null, requests a limited spot-check
343 // near the indicated recent changes in the class hierarchy.
344 // It is used by DepStream::spot_check_dependency_at.
346 // Detecting possible new assertions:
347 static Klass* find_unique_concrete_subtype(Klass* ctxk);
348 static Method* find_unique_concrete_method(Klass* ctxk, Method* m);
349 static int find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]);
351 // Create the encoding which will be stored in an nmethod.
352 void encode_content_bytes();
354 address content_bytes() {
355 assert(_content_bytes != NULL, "encode it first");
356 return _content_bytes;
357 }
358 size_t size_in_bytes() {
359 assert(_content_bytes != NULL, "encode it first");
360 return _size_in_bytes;
361 }
363 OopRecorder* oop_recorder() { return _oop_recorder; }
364 CompileLog* log() { return _log; }
366 void copy_to(nmethod* nm);
368 void log_all_dependencies();
370 void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) {
371 ResourceMark rm;
372 int argslen = args->length();
373 write_dependency_to(log(), dept, args);
374 guarantee(argslen == args->length(),
375 "args array cannot grow inside nested ResoureMark scope");
376 }
378 void log_dependency(DepType dept,
379 ciBaseObject* x0,
380 ciBaseObject* x1 = NULL,
381 ciBaseObject* x2 = NULL) {
382 if (log() == NULL) {
383 return;
384 }
385 ResourceMark rm;
386 GrowableArray<ciBaseObject*>* ciargs =
387 new GrowableArray<ciBaseObject*>(dep_args(dept));
388 assert (x0 != NULL, "no log x0");
389 ciargs->push(x0);
391 if (x1 != NULL) {
392 ciargs->push(x1);
393 }
394 if (x2 != NULL) {
395 ciargs->push(x2);
396 }
397 assert(ciargs->length() == dep_args(dept), "");
398 log_dependency(dept, ciargs);
399 }
401 class DepArgument : public ResourceObj {
402 private:
403 bool _is_oop;
404 bool _valid;
405 void* _value;
406 public:
407 DepArgument() : _is_oop(false), _value(NULL), _valid(false) {}
408 DepArgument(oop v): _is_oop(true), _value(v), _valid(true) {}
409 DepArgument(Metadata* v): _is_oop(false), _value(v), _valid(true) {}
411 bool is_null() const { return _value == NULL; }
412 bool is_oop() const { return _is_oop; }
413 bool is_metadata() const { return !_is_oop; }
414 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); }
415 bool is_method() const { return is_metadata() && metadata_value()->is_method(); }
417 oop oop_value() const { assert(_is_oop && _valid, "must be"); return (oop) _value; }
418 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; }
419 };
421 static void print_dependency(DepType dept,
422 GrowableArray<DepArgument>* args,
423 Klass* witness = NULL);
425 private:
426 // helper for encoding common context types as zero:
427 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x);
429 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x);
431 static void write_dependency_to(CompileLog* log,
432 DepType dept,
433 GrowableArray<ciBaseObject*>* args,
434 Klass* witness = NULL);
435 static void write_dependency_to(CompileLog* log,
436 DepType dept,
437 GrowableArray<DepArgument>* args,
438 Klass* witness = NULL);
439 static void write_dependency_to(xmlStream* xtty,
440 DepType dept,
441 GrowableArray<DepArgument>* args,
442 Klass* witness = NULL);
443 public:
444 // Use this to iterate over an nmethod's dependency set.
445 // Works on new and old dependency sets.
446 // Usage:
447 //
448 // ;
449 // Dependencies::DepType dept;
450 // for (Dependencies::DepStream deps(nm); deps.next(); ) {
451 // ...
452 // }
453 //
454 // The caller must be in the VM, since oops are not wrapped in handles.
455 class DepStream {
456 private:
457 nmethod* _code; // null if in a compiler thread
458 Dependencies* _deps; // null if not in a compiler thread
459 CompressedReadStream _bytes;
460 #ifdef ASSERT
461 size_t _byte_limit;
462 #endif
464 // iteration variables:
465 DepType _type;
466 int _xi[max_arg_count+1];
468 void initial_asserts(size_t byte_limit) NOT_DEBUG({});
470 inline Metadata* recorded_metadata_at(int i);
471 inline oop recorded_oop_at(int i);
473 Klass* check_klass_dependency(KlassDepChange* changes);
474 Klass* check_call_site_dependency(CallSiteDepChange* changes);
476 void trace_and_log_witness(Klass* witness);
478 public:
479 DepStream(Dependencies* deps)
480 : _deps(deps),
481 _code(NULL),
482 _bytes(deps->content_bytes())
483 {
484 initial_asserts(deps->size_in_bytes());
485 }
486 DepStream(nmethod* code)
487 : _deps(NULL),
488 _code(code),
489 _bytes(code->dependencies_begin())
490 {
491 initial_asserts(code->dependencies_size());
492 }
494 bool next();
496 DepType type() { return _type; }
497 int argument_count() { return dep_args(type()); }
498 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob");
499 return _xi[i]; }
500 Metadata* argument(int i); // => recorded_oop_at(argument_index(i))
501 oop argument_oop(int i); // => recorded_oop_at(argument_index(i))
502 Klass* context_type();
504 bool is_klass_type() { return Dependencies::is_klass_type(type()); }
506 Method* method_argument(int i) {
507 Metadata* x = argument(i);
508 assert(x->is_method(), "type");
509 return (Method*) x;
510 }
511 Klass* type_argument(int i) {
512 Metadata* x = argument(i);
513 assert(x->is_klass(), "type");
514 return (Klass*) x;
515 }
517 // The point of the whole exercise: Is this dep still OK?
518 Klass* check_dependency() {
519 Klass* result = check_klass_dependency(NULL);
520 if (result != NULL) return result;
521 return check_call_site_dependency(NULL);
522 }
524 // A lighter version: Checks only around recent changes in a class
525 // hierarchy. (See Universe::flush_dependents_on.)
526 Klass* spot_check_dependency_at(DepChange& changes);
528 // Log the current dependency to xtty or compilation log.
529 void log_dependency(Klass* witness = NULL);
531 // Print the current dependency to tty.
532 void print_dependency(Klass* witness = NULL, bool verbose = false);
533 };
534 friend class Dependencies::DepStream;
536 static void print_statistics() PRODUCT_RETURN;
537 };
540 // Every particular DepChange is a sub-class of this class.
541 class DepChange : public StackObj {
542 public:
543 // What kind of DepChange is this?
544 virtual bool is_klass_change() const { return false; }
545 virtual bool is_call_site_change() const { return false; }
547 // Subclass casting with assertions.
548 KlassDepChange* as_klass_change() {
549 assert(is_klass_change(), "bad cast");
550 return (KlassDepChange*) this;
551 }
552 CallSiteDepChange* as_call_site_change() {
553 assert(is_call_site_change(), "bad cast");
554 return (CallSiteDepChange*) this;
555 }
557 void print();
559 public:
560 enum ChangeType {
561 NO_CHANGE = 0, // an uninvolved klass
562 Change_new_type, // a newly loaded type
563 Change_new_sub, // a super with a new subtype
564 Change_new_impl, // an interface with a new implementation
565 CHANGE_LIMIT,
566 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream
567 };
569 // Usage:
570 // for (DepChange::ContextStream str(changes); str.next(); ) {
571 // Klass* k = str.klass();
572 // switch (str.change_type()) {
573 // ...
574 // }
575 // }
576 class ContextStream : public StackObj {
577 private:
578 DepChange& _changes;
579 friend class DepChange;
581 // iteration variables:
582 ChangeType _change_type;
583 Klass* _klass;
584 Array<Klass*>* _ti_base; // i.e., transitive_interfaces
585 int _ti_index;
586 int _ti_limit;
588 // start at the beginning:
589 void start();
591 public:
592 ContextStream(DepChange& changes)
593 : _changes(changes)
594 { start(); }
596 ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv)
597 : _changes(changes)
598 // the nsv argument makes it safe to hold oops like _klass
599 { start(); }
601 bool next();
603 ChangeType change_type() { return _change_type; }
604 Klass* klass() { return _klass; }
605 };
606 friend class DepChange::ContextStream;
607 };
610 // A class hierarchy change coming through the VM (under the Compile_lock).
611 // The change is structured as a single new type with any number of supers
612 // and implemented interface types. Other than the new type, any of the
613 // super types can be context types for a relevant dependency, which the
614 // new type could invalidate.
615 class KlassDepChange : public DepChange {
616 private:
617 // each change set is rooted in exactly one new type (at present):
618 KlassHandle _new_type;
620 void initialize();
622 public:
623 // notes the new type, marks it and all its super-types
624 KlassDepChange(KlassHandle new_type)
625 : _new_type(new_type)
626 {
627 initialize();
628 }
630 // cleans up the marks
631 ~KlassDepChange();
633 // What kind of DepChange is this?
634 virtual bool is_klass_change() const { return true; }
636 Klass* new_type() { return _new_type(); }
638 // involves_context(k) is true if k is new_type or any of the super types
639 bool involves_context(Klass* k);
640 };
643 // A CallSite has changed its target.
644 class CallSiteDepChange : public DepChange {
645 private:
646 Handle _call_site;
647 Handle _method_handle;
649 public:
650 CallSiteDepChange(Handle call_site, Handle method_handle)
651 : _call_site(call_site),
652 _method_handle(method_handle)
653 {
654 assert(_call_site() ->is_a(SystemDictionary::CallSite_klass()), "must be");
655 assert(_method_handle()->is_a(SystemDictionary::MethodHandle_klass()), "must be");
656 }
658 // What kind of DepChange is this?
659 virtual bool is_call_site_change() const { return true; }
661 oop call_site() const { return _call_site(); }
662 oop method_handle() const { return _method_handle(); }
663 };
665 #endif // SHARE_VM_CODE_DEPENDENCIES_HPP