1 /* 2 * Copyright (c) 2005, 2023, 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_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 end_marker = 0, 107 108 // An 'evol' dependency simply notes that the contents of the 109 // method were used. If it evolves (is replaced), the nmethod 110 // must be recompiled. No other dependencies are implied. 111 evol_method, 112 FIRST_TYPE = evol_method, 113 114 // A context type CX is a leaf it if has no proper subtype. 115 leaf_type, 116 117 // An abstract class CX has exactly one concrete subtype CC. 118 abstract_with_unique_concrete_subtype, 119 120 // Given a method M1 and a context class CX, the set MM(CX, M1) of 121 // "concrete matching methods" in CX of M1 is the set of every 122 // concrete M2 for which it is possible to create an invokevirtual 123 // or invokeinterface call site that can reach either M1 or M2. 124 // That is, M1 and M2 share a name, signature, and vtable index. 125 // We wish to notice when the set MM(CX, M1) is just {M1}, or 126 // perhaps a set of two {M1,M2}, and issue dependencies on this. 127 128 // The set MM(CX, M1) can be computed by starting with any matching 129 // concrete M2 that is inherited into CX, and then walking the 130 // subtypes* of CX looking for concrete definitions. 131 132 // The parameters to this dependency are the method M1 and the 133 // context class CX. M1 must be either inherited in CX or defined 134 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater 135 // than {M1}. 136 unique_concrete_method_2, // one unique concrete method under CX 137 138 // In addition to the method M1 and the context class CX, the parameters 139 // to this dependency are the resolved class RC1 and the 140 // resolved method RM1. It asserts that MM(CX, M1, RC1, RM1) 141 // is no greater than {M1}. RC1 and RM1 are used to improve the precision 142 // of the analysis. 143 unique_concrete_method_4, // one unique concrete method under CX 144 145 // This dependency asserts that interface CX has a unique implementor class. 146 unique_implementor, // one unique implementor under CX 147 148 // This dependency asserts that no instances of class or it's 149 // subclasses require finalization registration. 150 no_finalizable_subclasses, 151 152 // This dependency asserts when the CallSite.target value changed. 153 call_site_target_value, 154 155 TYPE_LIMIT 156 }; 157 enum { 158 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT)) 159 160 // handy categorizations of dependency types: 161 all_types = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE), 162 163 non_klass_types = (1 << call_site_target_value), 164 klass_types = all_types & ~non_klass_types, 165 166 non_ctxk_types = (1 << evol_method) | (1 << call_site_target_value), 167 implicit_ctxk_types = 0, 168 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types), 169 170 max_arg_count = 4, // current maximum number of arguments (incl. ctxk) 171 172 // A "context type" is a class or interface that 173 // provides context for evaluating a dependency. 174 // When present, it is one of the arguments (dep_context_arg). 175 // 176 // If a dependency does not have a context type, there is a 177 // default context, depending on the type of the dependency. 178 // This bit signals that a default context has been compressed away. 179 default_context_type_bit = (1<<LG2_TYPE_LIMIT) 180 }; 181 182 static const char* dep_name(DepType dept); 183 static int dep_args(DepType dept); 184 185 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); } 186 187 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); } 188 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); } 189 190 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; } 191 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; } 192 193 static void check_valid_dependency_type(DepType dept); 194 195 #if INCLUDE_JVMCI 196 // A Metadata* or object value recorded in an OopRecorder 197 class DepValue { 198 private: 199 // Unique identifier of the value within the associated OopRecorder that 200 // encodes both the category of the value (0: invalid, positive: metadata, negative: object) 201 // and the index within a category specific array (metadata: index + 1, object: -(index + 1)) 202 int _id; 203 204 public: 205 DepValue() : _id(0) {} 206 DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = nullptr) { 207 assert(candidate == nullptr || candidate->is_metadata(), "oops"); 208 if (candidate != nullptr && candidate->as_metadata(rec) == metadata) { 209 _id = candidate->_id; 210 } else { 211 _id = rec->find_index(metadata) + 1; 212 } 213 } 214 DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = nullptr) { 215 assert(candidate == nullptr || candidate->is_object(), "oops"); 216 if (candidate != nullptr && candidate->as_object(rec) == obj) { 217 _id = candidate->_id; 218 } else { 219 _id = -(rec->find_index(obj) + 1); 220 } 221 } 222 223 // Used to sort values in ascending order of index() with metadata values preceding object values 224 int sort_key() const { return -_id; } 225 226 bool operator == (const DepValue& other) const { return other._id == _id; } 227 228 bool is_valid() const { return _id != 0; } 229 int index() const { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; } 230 bool is_metadata() const { assert(is_valid(), "oops"); return _id > 0; } 231 bool is_object() const { assert(is_valid(), "oops"); return _id < 0; } 232 233 Metadata* as_metadata(OopRecorder* rec) const { assert(is_metadata(), "oops"); return rec->metadata_at(index()); } 234 Klass* as_klass(OopRecorder* rec) const { 235 Metadata* m = as_metadata(rec); 236 assert(m != nullptr, "as_metadata returned nullptr"); 237 assert(m->is_klass(), "oops"); 238 return (Klass*) m; 239 } 240 Method* as_method(OopRecorder* rec) const { 241 Metadata* m = as_metadata(rec); 242 assert(m != nullptr, "as_metadata returned nullptr"); 243 assert(m->is_method(), "oops"); 244 return (Method*) m; 245 } 246 jobject as_object(OopRecorder* rec) const { assert(is_object(), "oops"); return rec->oop_at(index()); } 247 }; 248 #endif // INCLUDE_JVMCI 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 != nullptr, "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 != nullptr, "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 static void check_unique_method(ciKlass* ctxk, ciMethod* m) { 334 assert(!m->can_be_statically_bound(ctxk->as_instance_klass()) || ctxk->is_interface(), "redundant"); 335 } 336 static void check_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk) { 337 assert(ctxk->implementor() == uniqk, "not a unique implementor"); 338 } 339 340 void assert_common_1(DepType dept, ciBaseObject* x); 341 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1); 342 void assert_common_4(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2, ciBaseObject* x3); 343 344 public: 345 // Adding assertions to a new dependency set at compile time: 346 void assert_evol_method(ciMethod* m); 347 void assert_leaf_type(ciKlass* ctxk); 348 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck); 349 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm); 350 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm, ciKlass* resolved_klass, ciMethod* resolved_method); 351 void assert_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk); 352 void assert_has_no_finalizable_subclasses(ciKlass* ctxk); 353 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle); 354 #if INCLUDE_JVMCI 355 private: 356 static void check_ctxk(Klass* ctxk) { 357 assert(ctxk->is_instance_klass(), "java types only"); 358 } 359 static void check_ctxk_abstract(Klass* ctxk) { 360 check_ctxk(ctxk); 361 assert(ctxk->is_abstract(), "must be abstract"); 362 } 363 static void check_unique_method(Klass* ctxk, Method* m) { 364 assert(!m->can_be_statically_bound(InstanceKlass::cast(ctxk)), "redundant"); 365 } 366 367 void assert_common_1(DepType dept, DepValue x); 368 void assert_common_2(DepType dept, DepValue x0, DepValue x1); 369 370 public: 371 void assert_evol_method(Method* m); 372 void assert_has_no_finalizable_subclasses(Klass* ctxk); 373 void assert_leaf_type(Klass* ctxk); 374 void assert_unique_implementor(InstanceKlass* ctxk, InstanceKlass* uniqk); 375 void assert_unique_concrete_method(Klass* ctxk, Method* uniqm); 376 void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck); 377 void assert_call_site_target_value(oop callSite, oop methodHandle); 378 #endif // INCLUDE_JVMCI 379 380 // Define whether a given method or type is concrete. 381 // These methods define the term "concrete" as used in this module. 382 // For this module, an "abstract" class is one which is non-concrete. 383 // 384 // Future optimizations may allow some classes to remain 385 // non-concrete until their first instantiation, and allow some 386 // methods to remain non-concrete until their first invocation. 387 // In that case, there would be a middle ground between concrete 388 // and abstract (as defined by the Java language and VM). 389 static bool is_concrete_klass(Klass* k); // k is instantiable 390 static bool is_concrete_method(Method* m, Klass* k); // m is invocable 391 static Klass* find_finalizable_subclass(InstanceKlass* ik); 392 393 static bool is_concrete_root_method(Method* uniqm, InstanceKlass* ctxk); 394 static Klass* find_witness_AME(InstanceKlass* ctxk, Method* m, KlassDepChange* changes = nullptr); 395 396 // These versions of the concreteness queries work through the CI. 397 // The CI versions are allowed to skew sometimes from the VM 398 // (oop-based) versions. The cost of such a difference is a 399 // (safely) aborted compilation, or a deoptimization, or a missed 400 // optimization opportunity. 401 // 402 // In order to prevent spurious assertions, query results must 403 // remain stable within any single ciEnv instance. (I.e., they must 404 // not go back into the VM to get their value; they must cache the 405 // bit in the CI, either eagerly or lazily.) 406 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable 407 static bool has_finalizable_subclass(ciInstanceKlass* k); 408 409 // As a general rule, it is OK to compile under the assumption that 410 // a given type or method is concrete, even if it at some future 411 // point becomes abstract. So dependency checking is one-sided, in 412 // that it permits supposedly concrete classes or methods to turn up 413 // as really abstract. (This shouldn't happen, except during class 414 // evolution, but that's the logic of the checking.) However, if a 415 // supposedly abstract class or method suddenly becomes concrete, a 416 // dependency on it must fail. 417 418 // Checking old assertions at run-time (in the VM only): 419 static Klass* check_evol_method(Method* m); 420 static Klass* check_leaf_type(InstanceKlass* ctxk); 421 static Klass* check_abstract_with_unique_concrete_subtype(InstanceKlass* ctxk, Klass* conck, NewKlassDepChange* changes = nullptr); 422 static Klass* check_unique_implementor(InstanceKlass* ctxk, Klass* uniqk, NewKlassDepChange* changes = nullptr); 423 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, NewKlassDepChange* changes = nullptr); 424 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, Klass* resolved_klass, Method* resolved_method, KlassDepChange* changes = nullptr); 425 static Klass* check_has_no_finalizable_subclasses(InstanceKlass* ctxk, NewKlassDepChange* changes = nullptr); 426 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = nullptr); 427 // A returned Klass* is nullptr if the dependency assertion is still 428 // valid. A non-nullptr Klass* is a 'witness' to the assertion 429 // failure, a point in the class hierarchy where the assertion has 430 // been proven false. For example, if check_leaf_type returns 431 // non-nullptr, the value is a subtype of the supposed leaf type. This 432 // witness value may be useful for logging the dependency failure. 433 // Note that, when a dependency fails, there may be several possible 434 // witnesses to the failure. The value returned from the check_foo 435 // method is chosen arbitrarily. 436 437 // The 'changes' value, if non-null, requests a limited spot-check 438 // near the indicated recent changes in the class hierarchy. 439 // It is used by DepStream::spot_check_dependency_at. 440 441 // Detecting possible new assertions: 442 static Klass* find_unique_concrete_subtype(InstanceKlass* ctxk); 443 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m, 444 Klass** participant = nullptr); // out parameter 445 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m, Klass* resolved_klass, Method* resolved_method); 446 447 #ifdef ASSERT 448 static bool verify_method_context(InstanceKlass* ctxk, Method* m); 449 #endif // ASSERT 450 451 // Create the encoding which will be stored in an nmethod. 452 void encode_content_bytes(); 453 454 address content_bytes() { 455 assert(_content_bytes != nullptr, "encode it first"); 456 return _content_bytes; 457 } 458 size_t size_in_bytes() { 459 assert(_content_bytes != nullptr, "encode it first"); 460 return _size_in_bytes; 461 } 462 463 OopRecorder* oop_recorder() { return _oop_recorder; } 464 CompileLog* log() { return _log; } 465 466 void copy_to(nmethod* nm); 467 468 static bool _verify_in_progress; // turn off logging dependencies 469 470 DepType validate_dependencies(CompileTask* task, char** failure_detail = nullptr); 471 472 void log_all_dependencies(); 473 474 void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) { 475 ResourceMark rm; 476 int argslen = args->length(); 477 write_dependency_to(log(), dept, args); 478 guarantee(argslen == args->length(), 479 "args array cannot grow inside nested ResoureMark scope"); 480 } 481 482 void log_dependency(DepType dept, 483 ciBaseObject* x0, 484 ciBaseObject* x1 = nullptr, 485 ciBaseObject* x2 = nullptr, 486 ciBaseObject* x3 = nullptr) { 487 if (log() == nullptr) { 488 return; 489 } 490 ResourceMark rm; 491 GrowableArray<ciBaseObject*>* ciargs = 492 new GrowableArray<ciBaseObject*>(dep_args(dept)); 493 assert (x0 != nullptr, "no log x0"); 494 ciargs->push(x0); 495 496 if (x1 != nullptr) { 497 ciargs->push(x1); 498 } 499 if (x2 != nullptr) { 500 ciargs->push(x2); 501 } 502 if (x3 != nullptr) { 503 ciargs->push(x3); 504 } 505 assert(ciargs->length() == dep_args(dept), ""); 506 log_dependency(dept, ciargs); 507 } 508 509 class DepArgument : public ResourceObj { 510 private: 511 bool _is_oop; 512 bool _valid; 513 void* _value; 514 public: 515 DepArgument() : _is_oop(false), _valid(false), _value(nullptr) {} 516 DepArgument(oop v): _is_oop(true), _valid(true), _value(v) {} 517 DepArgument(Metadata* v): _is_oop(false), _valid(true), _value(v) {} 518 519 bool is_null() const { return _value == nullptr; } 520 bool is_oop() const { return _is_oop; } 521 bool is_metadata() const { return !_is_oop; } 522 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); } 523 bool is_method() const { return is_metadata() && metadata_value()->is_method(); } 524 525 oop oop_value() const { assert(_is_oop && _valid, "must be"); return cast_to_oop(_value); } 526 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; } 527 }; 528 529 static void print_dependency(DepType dept, 530 GrowableArray<DepArgument>* args, 531 Klass* witness = nullptr, outputStream* st = tty); 532 533 private: 534 // helper for encoding common context types as zero: 535 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x); 536 537 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x); 538 539 static void write_dependency_to(CompileLog* log, 540 DepType dept, 541 GrowableArray<ciBaseObject*>* args, 542 Klass* witness = nullptr); 543 static void write_dependency_to(CompileLog* log, 544 DepType dept, 545 GrowableArray<DepArgument>* args, 546 Klass* witness = nullptr); 547 static void write_dependency_to(xmlStream* xtty, 548 DepType dept, 549 GrowableArray<DepArgument>* args, 550 Klass* witness = nullptr); 551 public: 552 // Use this to iterate over an nmethod's dependency set. 553 // Works on new and old dependency sets. 554 // Usage: 555 // 556 // ; 557 // Dependencies::DepType dept; 558 // for (Dependencies::DepStream deps(nm); deps.next(); ) { 559 // ... 560 // } 561 // 562 // The caller must be in the VM, since oops are not wrapped in handles. 563 class DepStream { 564 private: 565 nmethod* _code; // null if in a compiler thread 566 Dependencies* _deps; // null if not in a compiler thread 567 CompressedReadStream _bytes; 568 #ifdef ASSERT 569 size_t _byte_limit; 570 #endif 571 572 // iteration variables: 573 DepType _type; 574 int _xi[max_arg_count+1]; 575 576 void initial_asserts(size_t byte_limit) NOT_DEBUG({}); 577 578 inline Metadata* recorded_metadata_at(int i); 579 inline oop recorded_oop_at(int i); 580 581 Klass* check_klass_dependency(KlassDepChange* changes); 582 Klass* check_new_klass_dependency(NewKlassDepChange* changes); 583 Klass* check_klass_init_dependency(KlassInitDepChange* changes); 584 Klass* check_call_site_dependency(CallSiteDepChange* changes); 585 586 void trace_and_log_witness(Klass* witness); 587 588 public: 589 DepStream(Dependencies* deps) 590 : _code(nullptr), 591 _deps(deps), 592 _bytes(deps->content_bytes()) 593 { 594 initial_asserts(deps->size_in_bytes()); 595 } 596 DepStream(nmethod* code) 597 : _code(code), 598 _deps(nullptr), 599 _bytes(code->dependencies_begin()) 600 { 601 initial_asserts(code->dependencies_size()); 602 } 603 604 bool next(); 605 606 DepType type() { return _type; } 607 bool is_oop_argument(int i) { return type() == call_site_target_value; } 608 uintptr_t get_identifier(int i); 609 610 int argument_count() { return dep_args(type()); } 611 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); 612 return _xi[i]; } 613 Metadata* argument(int i); // => recorded_oop_at(argument_index(i)) 614 oop argument_oop(int i); // => recorded_oop_at(argument_index(i)) 615 InstanceKlass* context_type(); 616 617 bool is_klass_type() { return Dependencies::is_klass_type(type()); } 618 619 Method* method_argument(int i) { 620 Metadata* x = argument(i); 621 assert(x->is_method(), "type"); 622 return (Method*) x; 623 } 624 Klass* type_argument(int i) { 625 Metadata* x = argument(i); 626 assert(x->is_klass(), "type"); 627 return (Klass*) x; 628 } 629 630 // The point of the whole exercise: Is this dep still OK? 631 Klass* check_dependency() { 632 Klass* result = check_klass_dependency(nullptr); 633 if (result != nullptr) return result; 634 return check_call_site_dependency(nullptr); 635 } 636 637 // A lighter version: Checks only around recent changes in a class 638 // hierarchy. (See Universe::flush_dependents_on.) 639 Klass* spot_check_dependency_at(DepChange& changes); 640 641 // Log the current dependency to xtty or compilation log. 642 void log_dependency(Klass* witness = nullptr); 643 644 // Print the current dependency to tty. 645 void print_dependency(outputStream* st, Klass* witness = nullptr, bool verbose = false); 646 }; 647 friend class Dependencies::DepStream; 648 649 static void print_statistics(); 650 }; 651 652 653 class DependencySignature : public ResourceObj { 654 private: 655 int _args_count; 656 uintptr_t _argument_hash[Dependencies::max_arg_count]; 657 Dependencies::DepType _type; 658 659 public: 660 DependencySignature(Dependencies::DepStream& dep) { 661 _args_count = dep.argument_count(); 662 _type = dep.type(); 663 for (int i = 0; i < _args_count; i++) { 664 _argument_hash[i] = dep.get_identifier(i); 665 } 666 } 667 668 static bool equals(DependencySignature const& s1, DependencySignature const& s2); 669 static unsigned hash (DependencySignature const& s1) { return (unsigned)(s1.arg(0) >> 2); } 670 671 int args_count() const { return _args_count; } 672 uintptr_t arg(int idx) const { return _argument_hash[idx]; } 673 Dependencies::DepType type() const { return _type; } 674 675 }; 676 677 678 // Every particular DepChange is a sub-class of this class. 679 class DepChange : public StackObj { 680 public: 681 // What kind of DepChange is this? 682 virtual bool is_klass_change() const { return false; } 683 virtual bool is_new_klass_change() const { return false; } 684 virtual bool is_klass_init_change() const { return false; } 685 virtual bool is_call_site_change() const { return false; } 686 687 // Subclass casting with assertions. 688 KlassDepChange* as_klass_change() { 689 assert(is_klass_change(), "bad cast"); 690 return (KlassDepChange*) this; 691 } 692 NewKlassDepChange* as_new_klass_change() { 693 assert(is_new_klass_change(), "bad cast"); 694 return (NewKlassDepChange*) this; 695 } 696 KlassInitDepChange* as_klass_init_change() { 697 assert(is_klass_init_change(), "bad cast"); 698 return (KlassInitDepChange*) this; 699 } 700 CallSiteDepChange* as_call_site_change() { 701 assert(is_call_site_change(), "bad cast"); 702 return (CallSiteDepChange*) this; 703 } 704 705 void print(); 706 void print_on(outputStream* st); 707 708 public: 709 enum ChangeType { 710 NO_CHANGE = 0, // an uninvolved klass 711 Change_new_type, // a newly loaded type 712 Change_new_sub, // a super with a new subtype 713 Change_new_impl, // an interface with a new implementation 714 CHANGE_LIMIT, 715 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream 716 }; 717 718 // Usage: 719 // for (DepChange::ContextStream str(changes); str.next(); ) { 720 // InstanceKlass* k = str.klass(); 721 // switch (str.change_type()) { 722 // ... 723 // } 724 // } 725 class ContextStream : public StackObj { 726 private: 727 DepChange& _changes; 728 friend class DepChange; 729 730 // iteration variables: 731 ChangeType _change_type; 732 InstanceKlass* _klass; 733 Array<InstanceKlass*>* _ti_base; // i.e., transitive_interfaces 734 int _ti_index; 735 int _ti_limit; 736 737 // start at the beginning: 738 void start(); 739 740 public: 741 ContextStream(DepChange& changes) 742 : _changes(changes) 743 { start(); } 744 745 ContextStream(DepChange& changes, NoSafepointVerifier& nsv) 746 : _changes(changes) 747 // the nsv argument makes it safe to hold oops like _klass 748 { start(); } 749 750 bool next(); 751 752 ChangeType change_type() { return _change_type; } 753 InstanceKlass* klass() { return _klass; } 754 }; 755 friend class DepChange::ContextStream; 756 }; 757 758 759 // A class hierarchy change coming through the VM (under the Compile_lock). 760 // The change is structured as a single type with any number of supers 761 // and implemented interface types. Other than the type, any of the 762 // super types can be context types for a relevant dependency, which the 763 // type could invalidate. 764 class KlassDepChange : public DepChange { 765 private: 766 // each change set is rooted in exactly one type (at present): 767 InstanceKlass* _type; 768 769 void initialize(); 770 771 protected: 772 // notes the type, marks it and all its super-types 773 KlassDepChange(InstanceKlass* type) : _type(type) { 774 initialize(); 775 } 776 777 // cleans up the marks 778 ~KlassDepChange(); 779 780 public: 781 // What kind of DepChange is this? 782 virtual bool is_klass_change() const { return true; } 783 784 InstanceKlass* type() { return _type; } 785 786 // involves_context(k) is true if k == _type or any of its super types 787 bool involves_context(Klass* k); 788 }; 789 790 // A class hierarchy change: new type is loaded. 791 class NewKlassDepChange : public KlassDepChange { 792 public: 793 NewKlassDepChange(InstanceKlass* new_type) : KlassDepChange(new_type) {} 794 795 // What kind of DepChange is this? 796 virtual bool is_new_klass_change() const { return true; } 797 798 InstanceKlass* new_type() { return type(); } 799 }; 800 801 // Change in initialization state of a loaded class. 802 class KlassInitDepChange : public KlassDepChange { 803 public: 804 KlassInitDepChange(InstanceKlass* type) : KlassDepChange(type) {} 805 806 // What kind of DepChange is this? 807 virtual bool is_klass_init_change() const { return true; } 808 }; 809 810 // A CallSite has changed its target. 811 class CallSiteDepChange : public DepChange { 812 private: 813 Handle _call_site; 814 Handle _method_handle; 815 816 public: 817 CallSiteDepChange(Handle call_site, Handle method_handle); 818 819 // What kind of DepChange is this? 820 virtual bool is_call_site_change() const { return true; } 821 822 oop call_site() const { return _call_site(); } 823 oop method_handle() const { return _method_handle(); } 824 }; 825 826 #endif // SHARE_CODE_DEPENDENCIES_HPP