1 /* 2 * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 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 // _type is initially set to -1, to prevent "already at end" assert 107 undefined_dependency = -1, 108 109 end_marker = 0, 110 111 // An 'evol' dependency simply notes that the contents of the 112 // method were used. If it evolves (is replaced), the nmethod 113 // must be recompiled. No other dependencies are implied. 114 evol_method, 115 FIRST_TYPE = evol_method, 116 117 // A context type CX is a leaf it if has no proper subtype. 118 leaf_type, 119 120 // An abstract class CX has exactly one concrete subtype CC. 121 abstract_with_unique_concrete_subtype, 122 123 // Given a method M1 and a context class CX, the set MM(CX, M1) of 124 // "concrete matching methods" in CX of M1 is the set of every 125 // concrete M2 for which it is possible to create an invokevirtual 126 // or invokeinterface call site that can reach either M1 or M2. 127 // That is, M1 and M2 share a name, signature, and vtable index. 128 // We wish to notice when the set MM(CX, M1) is just {M1}, or 129 // perhaps a set of two {M1,M2}, and issue dependencies on this. 130 131 // The set MM(CX, M1) can be computed by starting with any matching 132 // concrete M2 that is inherited into CX, and then walking the 133 // subtypes* of CX looking for concrete definitions. 134 135 // The parameters to this dependency are the method M1 and the 136 // context class CX. M1 must be either inherited in CX or defined 137 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater 138 // than {M1}. 139 unique_concrete_method_2, // one unique concrete method under CX 140 141 // In addition to the method M1 and the context class CX, the parameters 142 // to this dependency are the resolved class RC1 and the 143 // resolved method RM1. It asserts that MM(CX, M1, RC1, RM1) 144 // is no greater than {M1}. RC1 and RM1 are used to improve the precision 145 // of the analysis. 146 unique_concrete_method_4, // one unique concrete method under CX 147 148 // This dependency asserts that interface CX has a unique implementor class. 149 unique_implementor, // one unique implementor under CX 150 151 // This dependency asserts that no instances of class or it's 152 // subclasses require finalization registration. 153 no_finalizable_subclasses, 154 155 // This dependency asserts when the CallSite.target value changed. 156 call_site_target_value, 157 158 TYPE_LIMIT 159 }; 160 enum { 161 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT)) 162 163 // handy categorizations of dependency types: 164 all_types = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE), 165 166 non_klass_types = (1 << call_site_target_value), 167 klass_types = all_types & ~non_klass_types, 168 169 non_ctxk_types = (1 << evol_method) | (1 << call_site_target_value), 170 implicit_ctxk_types = 0, 171 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types), 172 173 max_arg_count = 4, // current maximum number of arguments (incl. ctxk) 174 175 // A "context type" is a class or interface that 176 // provides context for evaluating a dependency. 177 // When present, it is one of the arguments (dep_context_arg). 178 // 179 // If a dependency does not have a context type, there is a 180 // default context, depending on the type of the dependency. 181 // This bit signals that a default context has been compressed away. 182 default_context_type_bit = (1<<LG2_TYPE_LIMIT) 183 }; 184 185 static const char* dep_name(DepType dept); 186 static int dep_args(DepType dept); 187 188 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); } 189 190 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); } 191 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); } 192 193 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; } 194 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; } 195 196 static void check_valid_dependency_type(DepType dept); 197 198 #if INCLUDE_JVMCI 199 // A Metadata* or object value recorded in an OopRecorder 200 class DepValue { 201 private: 202 // Unique identifier of the value within the associated OopRecorder that 203 // encodes both the category of the value (0: invalid, positive: metadata, negative: object) 204 // and the index within a category specific array (metadata: index + 1, object: -(index + 1)) 205 int _id; 206 207 public: 208 DepValue() : _id(0) {} 209 DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = nullptr) { 210 assert(candidate == nullptr || candidate->is_metadata(), "oops"); 211 if (candidate != nullptr && candidate->as_metadata(rec) == metadata) { 212 _id = candidate->_id; 213 } else { 214 _id = rec->find_index(metadata) + 1; 215 } 216 } 217 DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = nullptr) { 218 assert(candidate == nullptr || candidate->is_object(), "oops"); 219 if (candidate != nullptr && candidate->as_object(rec) == obj) { 220 _id = candidate->_id; 221 } else { 222 _id = -(rec->find_index(obj) + 1); 223 } 224 } 225 226 // Used to sort values in ascending order of index() with metadata values preceding object values 227 int sort_key() const { return -_id; } 228 229 bool operator == (const DepValue& other) const { return other._id == _id; } 230 231 bool is_valid() const { return _id != 0; } 232 int index() const { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; } 233 bool is_metadata() const { assert(is_valid(), "oops"); return _id > 0; } 234 bool is_object() const { assert(is_valid(), "oops"); return _id < 0; } 235 236 Metadata* as_metadata(OopRecorder* rec) const { assert(is_metadata(), "oops"); return rec->metadata_at(index()); } 237 Klass* as_klass(OopRecorder* rec) const { 238 Metadata* m = as_metadata(rec); 239 assert(m != nullptr, "as_metadata returned nullptr"); 240 assert(m->is_klass(), "oops"); 241 return (Klass*) m; 242 } 243 Method* as_method(OopRecorder* rec) const { 244 Metadata* m = as_metadata(rec); 245 assert(m != nullptr, "as_metadata returned nullptr"); 246 assert(m->is_method(), "oops"); 247 return (Method*) m; 248 } 249 jobject as_object(OopRecorder* rec) const { assert(is_object(), "oops"); return rec->oop_at(index()); } 250 }; 251 #endif // INCLUDE_JVMCI 252 253 private: 254 // State for writing a new set of dependencies: 255 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept)) 256 GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT]; 257 #if INCLUDE_JVMCI 258 bool _using_dep_values; 259 GrowableArray<DepValue>* _dep_values[TYPE_LIMIT]; 260 #endif 261 262 static const char* _dep_name[TYPE_LIMIT]; 263 static int _dep_args[TYPE_LIMIT]; 264 265 static bool dept_in_mask(DepType dept, int mask) { 266 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0; 267 } 268 269 bool note_dep_seen(int dept, ciBaseObject* x) { 270 assert(dept < BitsPerInt, "oob"); 271 int x_id = x->ident(); 272 assert(_dep_seen != nullptr, "deps must be writable"); 273 int seen = _dep_seen->at_grow(x_id, 0); 274 _dep_seen->at_put(x_id, seen | (1<<dept)); 275 // return true if we've already seen dept/x 276 return (seen & (1<<dept)) != 0; 277 } 278 279 #if INCLUDE_JVMCI 280 bool note_dep_seen(int dept, DepValue x) { 281 assert(dept < BitsPerInt, "oops"); 282 // place metadata deps at even indexes, object deps at odd indexes 283 int x_id = x.is_metadata() ? x.index() * 2 : (x.index() * 2) + 1; 284 assert(_dep_seen != nullptr, "deps must be writable"); 285 int seen = _dep_seen->at_grow(x_id, 0); 286 _dep_seen->at_put(x_id, seen | (1<<dept)); 287 // return true if we've already seen dept/x 288 return (seen & (1<<dept)) != 0; 289 } 290 #endif 291 292 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps, 293 int ctxk_i, ciKlass* ctxk); 294 #if INCLUDE_JVMCI 295 bool maybe_merge_ctxk(GrowableArray<DepValue>* deps, 296 int ctxk_i, DepValue ctxk); 297 #endif 298 299 void sort_all_deps(); 300 size_t estimate_size_in_bytes(); 301 302 // Initialize _deps, etc. 303 void initialize(ciEnv* env); 304 305 // State for making a new set of dependencies: 306 OopRecorder* _oop_recorder; 307 308 // Logging support 309 CompileLog* _log; 310 311 address _content_bytes; // everything but the oop references, encoded 312 size_t _size_in_bytes; 313 314 public: 315 // Make a new empty dependencies set. 316 Dependencies(ciEnv* env) { 317 initialize(env); 318 } 319 #if INCLUDE_JVMCI 320 Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log); 321 #endif 322 323 private: 324 // Check for a valid context type. 325 // Enforce the restriction against array types. 326 static void check_ctxk(ciKlass* ctxk) { 327 assert(ctxk->is_instance_klass(), "java types only"); 328 } 329 static void check_ctxk_concrete(ciKlass* ctxk) { 330 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete"); 331 } 332 static void check_ctxk_abstract(ciKlass* ctxk) { 333 check_ctxk(ctxk); 334 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract"); 335 } 336 static void check_unique_method(ciKlass* ctxk, ciMethod* m) { 337 assert(!m->can_be_statically_bound(ctxk->as_instance_klass()) || ctxk->is_interface(), "redundant"); 338 } 339 static void check_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk) { 340 assert(ctxk->implementor() == uniqk, "not a unique implementor"); 341 } 342 343 void assert_common_1(DepType dept, ciBaseObject* x); 344 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1); 345 void assert_common_4(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2, ciBaseObject* x3); 346 347 public: 348 // Adding assertions to a new dependency set at compile time: 349 void assert_evol_method(ciMethod* m); 350 void assert_leaf_type(ciKlass* ctxk); 351 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck); 352 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm); 353 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm, ciKlass* resolved_klass, ciMethod* resolved_method); 354 void assert_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk); 355 void assert_has_no_finalizable_subclasses(ciKlass* ctxk); 356 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle); 357 #if INCLUDE_JVMCI 358 private: 359 static void check_ctxk(Klass* ctxk) { 360 assert(ctxk->is_instance_klass(), "java types only"); 361 } 362 static void check_ctxk_abstract(Klass* ctxk) { 363 check_ctxk(ctxk); 364 assert(ctxk->is_abstract(), "must be abstract"); 365 } 366 static void check_unique_method(Klass* ctxk, Method* m) { 367 assert(!m->can_be_statically_bound(InstanceKlass::cast(ctxk)), "redundant"); 368 } 369 370 void assert_common_1(DepType dept, DepValue x); 371 void assert_common_2(DepType dept, DepValue x0, DepValue x1); 372 373 public: 374 void assert_evol_method(Method* m); 375 void assert_has_no_finalizable_subclasses(Klass* ctxk); 376 void assert_leaf_type(Klass* ctxk); 377 void assert_unique_implementor(InstanceKlass* ctxk, InstanceKlass* uniqk); 378 void assert_unique_concrete_method(Klass* ctxk, Method* uniqm); 379 void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck); 380 void assert_call_site_target_value(oop callSite, oop methodHandle); 381 #endif // INCLUDE_JVMCI 382 383 // Define whether a given method or type is concrete. 384 // These methods define the term "concrete" as used in this module. 385 // For this module, an "abstract" class is one which is non-concrete. 386 // 387 // Future optimizations may allow some classes to remain 388 // non-concrete until their first instantiation, and allow some 389 // methods to remain non-concrete until their first invocation. 390 // In that case, there would be a middle ground between concrete 391 // and abstract (as defined by the Java language and VM). 392 static bool is_concrete_klass(Klass* k); // k is instantiable 393 static bool is_concrete_method(Method* m, Klass* k); // m is invocable 394 static Klass* find_finalizable_subclass(InstanceKlass* ik); 395 396 static bool is_concrete_root_method(Method* uniqm, InstanceKlass* ctxk); 397 static Klass* find_witness_AME(InstanceKlass* ctxk, Method* m, KlassDepChange* changes = nullptr); 398 399 // These versions of the concreteness queries work through the CI. 400 // The CI versions are allowed to skew sometimes from the VM 401 // (oop-based) versions. The cost of such a difference is a 402 // (safely) aborted compilation, or a deoptimization, or a missed 403 // optimization opportunity. 404 // 405 // In order to prevent spurious assertions, query results must 406 // remain stable within any single ciEnv instance. (I.e., they must 407 // not go back into the VM to get their value; they must cache the 408 // bit in the CI, either eagerly or lazily.) 409 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable 410 static bool has_finalizable_subclass(ciInstanceKlass* k); 411 412 // As a general rule, it is OK to compile under the assumption that 413 // a given type or method is concrete, even if it at some future 414 // point becomes abstract. So dependency checking is one-sided, in 415 // that it permits supposedly concrete classes or methods to turn up 416 // as really abstract. (This shouldn't happen, except during class 417 // evolution, but that's the logic of the checking.) However, if a 418 // supposedly abstract class or method suddenly becomes concrete, a 419 // dependency on it must fail. 420 421 // Checking old assertions at run-time (in the VM only): 422 static Klass* check_evol_method(Method* m); 423 static Klass* check_leaf_type(InstanceKlass* ctxk); 424 static Klass* check_abstract_with_unique_concrete_subtype(InstanceKlass* ctxk, Klass* conck, NewKlassDepChange* changes = nullptr); 425 static Klass* check_unique_implementor(InstanceKlass* ctxk, Klass* uniqk, NewKlassDepChange* changes = nullptr); 426 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, NewKlassDepChange* changes = nullptr); 427 static Klass* check_unique_concrete_method(InstanceKlass* ctxk, Method* uniqm, Klass* resolved_klass, Method* resolved_method, KlassDepChange* changes = nullptr); 428 static Klass* check_has_no_finalizable_subclasses(InstanceKlass* ctxk, NewKlassDepChange* changes = nullptr); 429 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = nullptr); 430 // A returned Klass* is nullptr if the dependency assertion is still 431 // valid. A non-nullptr Klass* is a 'witness' to the assertion 432 // failure, a point in the class hierarchy where the assertion has 433 // been proven false. For example, if check_leaf_type returns 434 // non-nullptr, the value is a subtype of the supposed leaf type. This 435 // witness value may be useful for logging the dependency failure. 436 // Note that, when a dependency fails, there may be several possible 437 // witnesses to the failure. The value returned from the check_foo 438 // method is chosen arbitrarily. 439 440 // The 'changes' value, if non-null, requests a limited spot-check 441 // near the indicated recent changes in the class hierarchy. 442 // It is used by DepStream::spot_check_dependency_at. 443 444 // Detecting possible new assertions: 445 static Klass* find_unique_concrete_subtype(InstanceKlass* ctxk); 446 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m, 447 Klass** participant = nullptr); // out parameter 448 static Method* find_unique_concrete_method(InstanceKlass* ctxk, Method* m, Klass* resolved_klass, Method* resolved_method); 449 450 #ifdef ASSERT 451 static bool verify_method_context(InstanceKlass* ctxk, Method* m); 452 #endif // ASSERT 453 454 // Create the encoding which will be stored in an nmethod. 455 void encode_content_bytes(); 456 457 address content_bytes() { 458 assert(_content_bytes != nullptr, "encode it first"); 459 return _content_bytes; 460 } 461 size_t size_in_bytes() { 462 assert(_content_bytes != nullptr, "encode it first"); 463 return _size_in_bytes; 464 } 465 466 void set_content(address content_bytes, int size_in_bytes) { 467 assert(_content_bytes == nullptr, "not intialized expected"); 468 _content_bytes = content_bytes; 469 _size_in_bytes = size_in_bytes; 470 } 471 472 OopRecorder* oop_recorder() { return _oop_recorder; } 473 CompileLog* log() { return _log; } 474 475 void copy_to(nmethod* nm); 476 477 static bool _verify_in_progress; // turn off logging dependencies 478 479 DepType validate_dependencies(CompileTask* task, char** failure_detail = nullptr); 480 481 void log_all_dependencies(); 482 483 void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) { 484 ResourceMark rm; 485 int argslen = args->length(); 486 write_dependency_to(log(), dept, args); 487 guarantee(argslen == args->length(), 488 "args array cannot grow inside nested ResoureMark scope"); 489 } 490 491 void log_dependency(DepType dept, 492 ciBaseObject* x0, 493 ciBaseObject* x1 = nullptr, 494 ciBaseObject* x2 = nullptr, 495 ciBaseObject* x3 = nullptr) { 496 if (log() == nullptr) { 497 return; 498 } 499 ResourceMark rm; 500 GrowableArray<ciBaseObject*>* ciargs = 501 new GrowableArray<ciBaseObject*>(dep_args(dept)); 502 assert (x0 != nullptr, "no log x0"); 503 ciargs->push(x0); 504 505 if (x1 != nullptr) { 506 ciargs->push(x1); 507 } 508 if (x2 != nullptr) { 509 ciargs->push(x2); 510 } 511 if (x3 != nullptr) { 512 ciargs->push(x3); 513 } 514 assert(ciargs->length() == dep_args(dept), ""); 515 log_dependency(dept, ciargs); 516 } 517 518 class DepArgument : public ResourceObj { 519 private: 520 bool _is_oop; 521 bool _valid; 522 void* _value; 523 public: 524 DepArgument() : _is_oop(false), _valid(false), _value(nullptr) {} 525 DepArgument(oop v): _is_oop(true), _valid(true), _value(v) {} 526 DepArgument(Metadata* v): _is_oop(false), _valid(true), _value(v) {} 527 528 bool is_null() const { return _value == nullptr; } 529 bool is_oop() const { return _is_oop; } 530 bool is_metadata() const { return !_is_oop; } 531 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); } 532 bool is_method() const { return is_metadata() && metadata_value()->is_method(); } 533 534 oop oop_value() const { assert(_is_oop && _valid, "must be"); return cast_to_oop(_value); } 535 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; } 536 }; 537 538 static void print_dependency(DepType dept, 539 GrowableArray<DepArgument>* args, 540 Klass* witness = nullptr, outputStream* st = tty); 541 542 private: 543 // helper for encoding common context types as zero: 544 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x); 545 546 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x); 547 548 static void write_dependency_to(CompileLog* log, 549 DepType dept, 550 GrowableArray<ciBaseObject*>* args, 551 Klass* witness = nullptr); 552 static void write_dependency_to(CompileLog* log, 553 DepType dept, 554 GrowableArray<DepArgument>* args, 555 Klass* witness = nullptr); 556 static void write_dependency_to(xmlStream* xtty, 557 DepType dept, 558 GrowableArray<DepArgument>* args, 559 Klass* witness = nullptr); 560 public: 561 // Use this to iterate over an nmethod's dependency set. 562 // Works on new and old dependency sets. 563 // Usage: 564 // 565 // ; 566 // Dependencies::DepType dept; 567 // for (Dependencies::DepStream deps(nm); deps.next(); ) { 568 // ... 569 // } 570 // 571 // The caller must be in the VM, since oops are not wrapped in handles. 572 class DepStream { 573 private: 574 nmethod* _code; // null if in a compiler thread 575 Dependencies* _deps; // null if not in a compiler thread 576 CompressedReadStream _bytes; 577 #ifdef ASSERT 578 size_t _byte_limit; 579 #endif 580 581 // iteration variables: 582 DepType _type; 583 int _xi[max_arg_count+1]; 584 585 void initial_asserts(size_t byte_limit) NOT_DEBUG({}); 586 587 inline Metadata* recorded_metadata_at(int i); 588 inline oop recorded_oop_at(int i); 589 590 Klass* check_klass_dependency(KlassDepChange* changes); 591 Klass* check_new_klass_dependency(NewKlassDepChange* changes); 592 Klass* check_klass_init_dependency(KlassInitDepChange* changes); 593 Klass* check_call_site_dependency(CallSiteDepChange* changes); 594 595 void trace_and_log_witness(Klass* witness); 596 597 public: 598 DepStream(Dependencies* deps) 599 : _code(nullptr), 600 _deps(deps), 601 _bytes(deps->content_bytes()) 602 { 603 initial_asserts(deps->size_in_bytes()); 604 } 605 DepStream(nmethod* code) 606 : _code(code), 607 _deps(nullptr), 608 _bytes(code->dependencies_begin()) 609 { 610 initial_asserts(code->dependencies_size()); 611 } 612 613 bool next(); 614 615 DepType type() { return _type; } 616 bool is_oop_argument(int i) { return type() == call_site_target_value; } 617 uintptr_t get_identifier(int i); 618 619 int argument_count() { return dep_args(type()); } 620 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); 621 return _xi[i]; } 622 Metadata* argument(int i); // => recorded_oop_at(argument_index(i)) 623 oop argument_oop(int i); // => recorded_oop_at(argument_index(i)) 624 InstanceKlass* context_type(); 625 626 bool is_klass_type() { return Dependencies::is_klass_type(type()); } 627 628 Method* method_argument(int i) { 629 Metadata* x = argument(i); 630 assert(x->is_method(), "type"); 631 return (Method*) x; 632 } 633 Klass* type_argument(int i) { 634 Metadata* x = argument(i); 635 assert(x->is_klass(), "type"); 636 return (Klass*) x; 637 } 638 639 // The point of the whole exercise: Is this dep still OK? 640 Klass* check_dependency() { 641 Klass* result = check_klass_dependency(nullptr); 642 if (result != nullptr) return result; 643 return check_call_site_dependency(nullptr); 644 } 645 646 // A lighter version: Checks only around recent changes in a class 647 // hierarchy. (See Universe::flush_dependents_on.) 648 Klass* spot_check_dependency_at(DepChange& changes); 649 650 // Log the current dependency to xtty or compilation log. 651 void log_dependency(Klass* witness = nullptr); 652 653 // Print the current dependency to tty. 654 void print_dependency(outputStream* st, Klass* witness = nullptr, bool verbose = false); 655 }; 656 friend class Dependencies::DepStream; 657 658 static void print_statistics(); 659 }; 660 661 662 class DependencySignature : public ResourceObj { 663 private: 664 int _args_count; 665 uintptr_t _argument_hash[Dependencies::max_arg_count]; 666 Dependencies::DepType _type; 667 668 public: 669 DependencySignature(Dependencies::DepStream& dep) { 670 _args_count = dep.argument_count(); 671 _type = dep.type(); 672 for (int i = 0; i < _args_count; i++) { 673 _argument_hash[i] = dep.get_identifier(i); 674 } 675 } 676 677 static bool equals(DependencySignature const& s1, DependencySignature const& s2); 678 static unsigned hash (DependencySignature const& s1) { return (unsigned)(s1.arg(0) >> 2); } 679 680 int args_count() const { return _args_count; } 681 uintptr_t arg(int idx) const { return _argument_hash[idx]; } 682 Dependencies::DepType type() const { return _type; } 683 684 }; 685 686 687 // Every particular DepChange is a sub-class of this class. 688 class DepChange : public StackObj { 689 public: 690 // What kind of DepChange is this? 691 virtual bool is_klass_change() const { return false; } 692 virtual bool is_new_klass_change() const { return false; } 693 virtual bool is_klass_init_change() const { return false; } 694 virtual bool is_call_site_change() const { return false; } 695 696 // Subclass casting with assertions. 697 KlassDepChange* as_klass_change() { 698 assert(is_klass_change(), "bad cast"); 699 return (KlassDepChange*) this; 700 } 701 NewKlassDepChange* as_new_klass_change() { 702 assert(is_new_klass_change(), "bad cast"); 703 return (NewKlassDepChange*) this; 704 } 705 KlassInitDepChange* as_klass_init_change() { 706 assert(is_klass_init_change(), "bad cast"); 707 return (KlassInitDepChange*) this; 708 } 709 CallSiteDepChange* as_call_site_change() { 710 assert(is_call_site_change(), "bad cast"); 711 return (CallSiteDepChange*) this; 712 } 713 714 void print(); 715 void print_on(outputStream* st); 716 717 public: 718 enum ChangeType { 719 NO_CHANGE = 0, // an uninvolved klass 720 Change_new_type, // a newly loaded type 721 Change_new_sub, // a super with a new subtype 722 Change_new_impl, // an interface with a new implementation 723 CHANGE_LIMIT, 724 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream 725 }; 726 727 // Usage: 728 // for (DepChange::ContextStream str(changes); str.next(); ) { 729 // InstanceKlass* k = str.klass(); 730 // switch (str.change_type()) { 731 // ... 732 // } 733 // } 734 class ContextStream : public StackObj { 735 private: 736 DepChange& _changes; 737 friend class DepChange; 738 739 // iteration variables: 740 ChangeType _change_type; 741 InstanceKlass* _klass; 742 Array<InstanceKlass*>* _ti_base; // i.e., transitive_interfaces 743 int _ti_index; 744 int _ti_limit; 745 746 // start at the beginning: 747 void start(); 748 749 public: 750 ContextStream(DepChange& changes) 751 : _changes(changes) 752 { start(); } 753 754 ContextStream(DepChange& changes, NoSafepointVerifier& nsv) 755 : _changes(changes) 756 // the nsv argument makes it safe to hold oops like _klass 757 { start(); } 758 759 bool next(); 760 761 ChangeType change_type() { return _change_type; } 762 InstanceKlass* klass() { return _klass; } 763 }; 764 friend class DepChange::ContextStream; 765 }; 766 767 768 // A class hierarchy change coming through the VM (under the Compile_lock). 769 // The change is structured as a single type with any number of supers 770 // and implemented interface types. Other than the type, any of the 771 // super types can be context types for a relevant dependency, which the 772 // type could invalidate. 773 class KlassDepChange : public DepChange { 774 private: 775 // each change set is rooted in exactly one type (at present): 776 InstanceKlass* _type; 777 778 void initialize(); 779 780 protected: 781 // notes the type, marks it and all its super-types 782 KlassDepChange(InstanceKlass* type) : _type(type) { 783 initialize(); 784 } 785 786 // cleans up the marks 787 ~KlassDepChange(); 788 789 public: 790 // What kind of DepChange is this? 791 virtual bool is_klass_change() const { return true; } 792 793 InstanceKlass* type() { return _type; } 794 795 // involves_context(k) is true if k == _type or any of its super types 796 bool involves_context(Klass* k); 797 }; 798 799 // A class hierarchy change: new type is loaded. 800 class NewKlassDepChange : public KlassDepChange { 801 public: 802 NewKlassDepChange(InstanceKlass* new_type) : KlassDepChange(new_type) {} 803 804 // What kind of DepChange is this? 805 virtual bool is_new_klass_change() const { return true; } 806 807 InstanceKlass* new_type() { return type(); } 808 }; 809 810 // Change in initialization state of a loaded class. 811 class KlassInitDepChange : public KlassDepChange { 812 public: 813 KlassInitDepChange(InstanceKlass* type) : KlassDepChange(type) {} 814 815 // What kind of DepChange is this? 816 virtual bool is_klass_init_change() const { return true; } 817 }; 818 819 // A CallSite has changed its target. 820 class CallSiteDepChange : public DepChange { 821 private: 822 Handle _call_site; 823 Handle _method_handle; 824 825 public: 826 CallSiteDepChange(Handle call_site, Handle method_handle); 827 828 // What kind of DepChange is this? 829 virtual bool is_call_site_change() const { return true; } 830 831 oop call_site() const { return _call_site(); } 832 oop method_handle() const { return _method_handle(); } 833 }; 834 835 #endif // SHARE_CODE_DEPENDENCIES_HPP --- EOF ---