1 /* 2 * Copyright (c) 2005, 2012, 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 #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 "utilities/growableArray.hpp" 35 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. 51 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; 61 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, 102 103 // 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, 108 109 // A context type CX is a leaf it if has no proper subtype. 110 leaf_type, 111 112 // An abstract class CX has exactly one concrete subtype CC. 113 abstract_with_unique_concrete_subtype, 114 115 // The type CX is purely abstract, with no concrete subtype* at all. 116 abstract_with_no_concrete_subtype, 117 118 // The concrete CX is free of concrete proper subtypes. 119 concrete_with_no_concrete_subtype, 120 121 // 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. 128 129 // 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. 132 133 // 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 138 139 // 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. 144 145 // 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, 152 153 // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}. 154 exclusive_concrete_methods_2, 155 156 // This dependency asserts that no instances of class or it's 157 // subclasses require finalization registration. 158 no_finalizable_subclasses, 159 160 // This dependency asserts when the CallSite.target value changed. 161 call_site_target_value, 162 163 TYPE_LIMIT 164 }; 165 enum { 166 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT)) 167 168 // handy categorizations of dependency types: 169 all_types = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE), 170 171 non_klass_types = (1 << call_site_target_value), 172 klass_types = all_types & ~non_klass_types, 173 174 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), 177 178 max_arg_count = 3, // current maximum number of arguments (incl. ctxk) 179 180 // 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 }; 189 190 static const char* dep_name(DepType dept); 191 static int dep_args(DepType dept); 192 193 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); } 194 195 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); } 197 198 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; } 200 201 static void check_valid_dependency_type(DepType dept); 202 203 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]; 207 208 static const char* _dep_name[TYPE_LIMIT]; 209 static int _dep_args[TYPE_LIMIT]; 210 211 static bool dept_in_mask(DepType dept, int mask) { 212 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0; 213 } 214 215 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 } 224 225 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps, 226 int ctxk_i, ciKlass* ctxk); 227 228 void sort_all_deps(); 229 size_t estimate_size_in_bytes(); 230 231 // Initialize _deps, etc. 232 void initialize(ciEnv* env); 233 234 // State for making a new set of dependencies: 235 OopRecorder* _oop_recorder; 236 237 // Logging support 238 CompileLog* _log; 239 240 address _content_bytes; // everything but the oop references, encoded 241 size_t _size_in_bytes; 242 243 public: 244 // Make a new empty dependencies set. 245 Dependencies(ciEnv* env) { 246 initialize(env); 247 } 248 249 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 } 262 263 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); 266 267 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); 279 280 // 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); // m is invocable 291 static Klass* find_finalizable_subclass(Klass* k); 292 293 // 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 is_concrete_method(ciMethod* m); // m appears invocable 305 static bool has_finalizable_subclass(ciInstanceKlass* k); 306 307 // As a general rule, it is OK to compile under the assumption that 308 // a given type or method is concrete, even if it at some future 309 // point becomes abstract. So dependency checking is one-sided, in 310 // that it permits supposedly concrete classes or methods to turn up 311 // as really abstract. (This shouldn't happen, except during class 312 // evolution, but that's the logic of the checking.) However, if a 313 // supposedly abstract class or method suddenly becomes concrete, a 314 // dependency on it must fail. 315 316 // Checking old assertions at run-time (in the VM only): 317 static Klass* check_evol_method(Method* m); 318 static Klass* check_leaf_type(Klass* ctxk); 319 static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck, 320 KlassDepChange* changes = NULL); 321 static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk, 322 KlassDepChange* changes = NULL); 323 static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk, 324 KlassDepChange* changes = NULL); 325 static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm, 326 KlassDepChange* changes = NULL); 327 static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2, 328 KlassDepChange* changes = NULL); 329 static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2, 330 KlassDepChange* changes = NULL); 331 static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL); 332 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL); 333 // A returned Klass* is NULL if the dependency assertion is still 334 // valid. A non-NULL Klass* is a 'witness' to the assertion 335 // failure, a point in the class hierarchy where the assertion has 336 // been proven false. For example, if check_leaf_type returns 337 // non-NULL, the value is a subtype of the supposed leaf type. This 338 // witness value may be useful for logging the dependency failure. 339 // Note that, when a dependency fails, there may be several possible 340 // witnesses to the failure. The value returned from the check_foo 341 // method is chosen arbitrarily. 342 343 // The 'changes' value, if non-null, requests a limited spot-check 344 // near the indicated recent changes in the class hierarchy. 345 // It is used by DepStream::spot_check_dependency_at. 346 347 // Detecting possible new assertions: 348 static Klass* find_unique_concrete_subtype(Klass* ctxk); 349 static Method* find_unique_concrete_method(Klass* ctxk, Method* m); 350 static int find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]); 351 static int find_exclusive_concrete_methods(Klass* ctxk, int mlen, Method* m[]); 352 353 // Create the encoding which will be stored in an nmethod. 354 void encode_content_bytes(); 355 356 address content_bytes() { 357 assert(_content_bytes != NULL, "encode it first"); 358 return _content_bytes; 359 } 360 size_t size_in_bytes() { 361 assert(_content_bytes != NULL, "encode it first"); 362 return _size_in_bytes; 363 } 364 365 OopRecorder* oop_recorder() { return _oop_recorder; } 366 CompileLog* log() { return _log; } 367 368 void copy_to(nmethod* nm); 369 370 void log_all_dependencies(); 371 void log_dependency(DepType dept, int nargs, ciBaseObject* args[]) { 372 write_dependency_to(log(), dept, nargs, args); 373 } 374 void log_dependency(DepType dept, 375 ciBaseObject* x0, 376 ciBaseObject* x1 = NULL, 377 ciBaseObject* x2 = NULL) { 378 if (log() == NULL) return; 379 ciBaseObject* args[max_arg_count]; 380 args[0] = x0; 381 args[1] = x1; 382 args[2] = x2; 383 assert(2 < max_arg_count, ""); 384 log_dependency(dept, dep_args(dept), args); 385 } 386 387 class DepArgument : public ResourceObj { 388 private: 389 bool _is_oop; 390 bool _valid; 391 void* _value; 392 public: 393 DepArgument() : _is_oop(false), _value(NULL), _valid(false) {} 394 DepArgument(oop v): _is_oop(true), _value(v), _valid(true) {} 395 DepArgument(Metadata* v): _is_oop(false), _value(v), _valid(true) {} 396 397 bool is_null() const { return _value == NULL; } 398 bool is_oop() const { return _is_oop; } 399 bool is_metadata() const { return !_is_oop; } 400 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); } 401 bool is_method() const { return is_metadata() && metadata_value()->is_method(); } 402 403 oop oop_value() const { assert(_is_oop && _valid, "must be"); return (oop) _value; } 404 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; } 405 }; 406 407 static void write_dependency_to(CompileLog* log, 408 DepType dept, 409 int nargs, ciBaseObject* args[], 410 Klass* witness = NULL); 411 static void write_dependency_to(CompileLog* log, 412 DepType dept, 413 int nargs, DepArgument args[], 414 Klass* witness = NULL); 415 static void write_dependency_to(xmlStream* xtty, 416 DepType dept, 417 int nargs, DepArgument args[], 418 Klass* witness = NULL); 419 static void print_dependency(DepType dept, 420 int nargs, DepArgument args[], 421 Klass* witness = NULL); 422 423 private: 424 // helper for encoding common context types as zero: 425 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x); 426 427 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x); 428 429 public: 430 // Use this to iterate over an nmethod's dependency set. 431 // Works on new and old dependency sets. 432 // Usage: 433 // 434 // ; 435 // Dependencies::DepType dept; 436 // for (Dependencies::DepStream deps(nm); deps.next(); ) { 437 // ... 438 // } 439 // 440 // The caller must be in the VM, since oops are not wrapped in handles. 441 class DepStream { 442 private: 443 nmethod* _code; // null if in a compiler thread 444 Dependencies* _deps; // null if not in a compiler thread 445 CompressedReadStream _bytes; 446 #ifdef ASSERT 447 size_t _byte_limit; 448 #endif 449 450 // iteration variables: 451 DepType _type; 452 int _xi[max_arg_count+1]; 453 454 void initial_asserts(size_t byte_limit) NOT_DEBUG({}); 455 456 inline Metadata* recorded_metadata_at(int i); 457 inline oop recorded_oop_at(int i); 458 459 Klass* check_klass_dependency(KlassDepChange* changes); 460 Klass* check_call_site_dependency(CallSiteDepChange* changes); 461 462 void trace_and_log_witness(Klass* witness); 463 464 public: 465 DepStream(Dependencies* deps) 466 : _deps(deps), 467 _code(NULL), 468 _bytes(deps->content_bytes()) 469 { 470 initial_asserts(deps->size_in_bytes()); 471 } 472 DepStream(nmethod* code) 473 : _deps(NULL), 474 _code(code), 475 _bytes(code->dependencies_begin()) 476 { 477 initial_asserts(code->dependencies_size()); 478 } 479 480 bool next(); 481 482 DepType type() { return _type; } 483 int argument_count() { return dep_args(type()); } 484 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); 485 return _xi[i]; } 486 Metadata* argument(int i); // => recorded_oop_at(argument_index(i)) 487 oop argument_oop(int i); // => recorded_oop_at(argument_index(i)) 488 Klass* context_type(); 489 490 bool is_klass_type() { return Dependencies::is_klass_type(type()); } 491 492 Method* method_argument(int i) { 493 Metadata* x = argument(i); 494 assert(x->is_method(), "type"); 495 return (Method*) x; 496 } 497 Klass* type_argument(int i) { 498 Metadata* x = argument(i); 499 assert(x->is_klass(), "type"); 500 return (Klass*) x; 501 } 502 503 // The point of the whole exercise: Is this dep still OK? 504 Klass* check_dependency() { 505 Klass* result = check_klass_dependency(NULL); 506 if (result != NULL) return result; 507 return check_call_site_dependency(NULL); 508 } 509 510 // A lighter version: Checks only around recent changes in a class 511 // hierarchy. (See Universe::flush_dependents_on.) 512 Klass* spot_check_dependency_at(DepChange& changes); 513 514 // Log the current dependency to xtty or compilation log. 515 void log_dependency(Klass* witness = NULL); 516 517 // Print the current dependency to tty. 518 void print_dependency(Klass* witness = NULL, bool verbose = false); 519 }; 520 friend class Dependencies::DepStream; 521 522 static void print_statistics() PRODUCT_RETURN; 523 }; 524 525 526 // Every particular DepChange is a sub-class of this class. 527 class DepChange : public StackObj { 528 public: 529 // What kind of DepChange is this? 530 virtual bool is_klass_change() const { return false; } 531 virtual bool is_call_site_change() const { return false; } 532 533 // Subclass casting with assertions. 534 KlassDepChange* as_klass_change() { 535 assert(is_klass_change(), "bad cast"); 536 return (KlassDepChange*) this; 537 } 538 CallSiteDepChange* as_call_site_change() { 539 assert(is_call_site_change(), "bad cast"); 540 return (CallSiteDepChange*) this; 541 } 542 543 void print(); 544 545 public: 546 enum ChangeType { 547 NO_CHANGE = 0, // an uninvolved klass 548 Change_new_type, // a newly loaded type 549 Change_new_sub, // a super with a new subtype 550 Change_new_impl, // an interface with a new implementation 551 CHANGE_LIMIT, 552 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream 553 }; 554 555 // Usage: 556 // for (DepChange::ContextStream str(changes); str.next(); ) { 557 // Klass* k = str.klass(); 558 // switch (str.change_type()) { 559 // ... 560 // } 561 // } 562 class ContextStream : public StackObj { 563 private: 564 DepChange& _changes; 565 friend class DepChange; 566 567 // iteration variables: 568 ChangeType _change_type; 569 Klass* _klass; 570 Array<Klass*>* _ti_base; // i.e., transitive_interfaces 571 int _ti_index; 572 int _ti_limit; 573 574 // start at the beginning: 575 void start(); 576 577 public: 578 ContextStream(DepChange& changes) 579 : _changes(changes) 580 { start(); } 581 582 ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv) 583 : _changes(changes) 584 // the nsv argument makes it safe to hold oops like _klass 585 { start(); } 586 587 bool next(); 588 589 ChangeType change_type() { return _change_type; } 590 Klass* klass() { return _klass; } 591 }; 592 friend class DepChange::ContextStream; 593 }; 594 595 596 // A class hierarchy change coming through the VM (under the Compile_lock). 597 // The change is structured as a single new type with any number of supers 598 // and implemented interface types. Other than the new type, any of the 599 // super types can be context types for a relevant dependency, which the 600 // new type could invalidate. 601 class KlassDepChange : public DepChange { 602 private: 603 // each change set is rooted in exactly one new type (at present): 604 KlassHandle _new_type; 605 606 void initialize(); 607 608 public: 609 // notes the new type, marks it and all its super-types 610 KlassDepChange(KlassHandle new_type) 611 : _new_type(new_type) 612 { 613 initialize(); 614 } 615 616 // cleans up the marks 617 ~KlassDepChange(); 618 619 // What kind of DepChange is this? 620 virtual bool is_klass_change() const { return true; } 621 622 Klass* new_type() { return _new_type(); } 623 624 // involves_context(k) is true if k is new_type or any of the super types 625 bool involves_context(Klass* k); 626 }; 627 628 629 // A CallSite has changed its target. 630 class CallSiteDepChange : public DepChange { 631 private: 632 Handle _call_site; 633 Handle _method_handle; 634 635 public: 636 CallSiteDepChange(Handle call_site, Handle method_handle) 637 : _call_site(call_site), 638 _method_handle(method_handle) 639 { 640 assert(_call_site() ->is_a(SystemDictionary::CallSite_klass()), "must be"); 641 assert(_method_handle()->is_a(SystemDictionary::MethodHandle_klass()), "must be"); 642 } 643 644 // What kind of DepChange is this? 645 virtual bool is_call_site_change() const { return true; } 646 647 oop call_site() const { return _call_site(); } 648 oop method_handle() const { return _method_handle(); } 649 }; 650 651 #endif // SHARE_VM_CODE_DEPENDENCIES_HPP