1 /* 2 * Copyright (c) 2005, 2019, 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 "classfile/systemDictionary.hpp" 33 #include "code/compressedStream.hpp" 34 #include "code/nmethod.hpp" 35 #include "memory/resourceArea.hpp" 36 #include "runtime/safepointVerifiers.hpp" 37 #include "utilities/growableArray.hpp" 38 #include "utilities/hashtable.hpp" 39 40 //** Dependencies represent assertions (approximate invariants) within 41 // the runtime system, e.g. class hierarchy changes. An example is an 42 // assertion that a given method is not overridden; another example is 43 // that a type has only one concrete subtype. Compiled code which 44 // relies on such assertions must be discarded if they are overturned 45 // by changes in the runtime system. We can think of these assertions 46 // as approximate invariants, because we expect them to be overturned 47 // very infrequently. We are willing to perform expensive recovery 48 // operations when they are overturned. The benefit, of course, is 49 // performing optimistic optimizations (!) on the object code. 50 // 51 // Changes in the class hierarchy due to dynamic linking or 52 // class evolution can violate dependencies. There is enough 53 // indexing between classes and nmethods to make dependency 54 // checking reasonably efficient. 55 56 class ciEnv; 57 class nmethod; 58 class OopRecorder; 59 class xmlStream; 60 class CompileLog; 61 class DepChange; 62 class KlassDepChange; 63 class CallSiteDepChange; 64 class NoSafepointVerifier; 65 66 class Dependencies: public ResourceObj { 67 public: 68 // Note: In the comments on dependency types, most uses of the terms 69 // subtype and supertype are used in a "non-strict" or "inclusive" 70 // sense, and are starred to remind the reader of this fact. 71 // Strict uses of the terms use the word "proper". 72 // 73 // Specifically, every class is its own subtype* and supertype*. 74 // (This trick is easier than continually saying things like "Y is a 75 // subtype of X or X itself".) 76 // 77 // Sometimes we write X > Y to mean X is a proper supertype of Y. 78 // The notation X > {Y, Z} means X has proper subtypes Y, Z. 79 // The notation X.m > Y means that Y inherits m from X, while 80 // X.m > Y.m means Y overrides X.m. A star denotes abstractness, 81 // as *I > A, meaning (abstract) interface I is a super type of A, 82 // or A.*m > B.m, meaning B.m implements abstract method A.m. 83 // 84 // In this module, the terms "subtype" and "supertype" refer to 85 // Java-level reference type conversions, as detected by 86 // "instanceof" and performed by "checkcast" operations. The method 87 // Klass::is_subtype_of tests these relations. Note that "subtype" 88 // is richer than "subclass" (as tested by Klass::is_subclass_of), 89 // since it takes account of relations involving interface and array 90 // types. 91 // 92 // To avoid needless complexity, dependencies involving array types 93 // are not accepted. If you need to make an assertion about an 94 // array type, make the assertion about its corresponding element 95 // types. Any assertion that might change about an array type can 96 // be converted to an assertion about its element type. 97 // 98 // Most dependencies are evaluated over a "context type" CX, which 99 // stands for the set Subtypes(CX) of every Java type that is a subtype* 100 // of CX. When the system loads a new class or interface N, it is 101 // responsible for re-evaluating changed dependencies whose context 102 // type now includes N, that is, all super types of N. 103 // 104 enum DepType { 105 end_marker = 0, 106 107 // An 'evol' dependency simply notes that the contents of the 108 // method were used. If it evolves (is replaced), the nmethod 109 // must be recompiled. No other dependencies are implied. 110 evol_method, 111 FIRST_TYPE = evol_method, 112 113 // A context type CX is a leaf it if has no proper subtype. 114 leaf_type, 115 116 // An abstract class CX has exactly one concrete subtype CC. 117 abstract_with_unique_concrete_subtype, 118 119 // The type CX is purely abstract, with no concrete subtype* at all. 120 abstract_with_no_concrete_subtype, 121 122 // The concrete CX is free of concrete proper subtypes. 123 concrete_with_no_concrete_subtype, 124 125 // Given a method M1 and a context class CX, the set MM(CX, M1) of 126 // "concrete matching methods" in CX of M1 is the set of every 127 // concrete M2 for which it is possible to create an invokevirtual 128 // or invokeinterface call site that can reach either M1 or M2. 129 // That is, M1 and M2 share a name, signature, and vtable index. 130 // We wish to notice when the set MM(CX, M1) is just {M1}, or 131 // perhaps a set of two {M1,M2}, and issue dependencies on this. 132 133 // The set MM(CX, M1) can be computed by starting with any matching 134 // concrete M2 that is inherited into CX, and then walking the 135 // subtypes* of CX looking for concrete definitions. 136 137 // The parameters to this dependency are the method M1 and the 138 // context class CX. M1 must be either inherited in CX or defined 139 // in a subtype* of CX. It asserts that MM(CX, M1) is no greater 140 // than {M1}. 141 unique_concrete_method, // one unique concrete method under CX 142 143 // An "exclusive" assertion concerns two methods or subtypes, and 144 // declares that there are at most two (or perhaps later N>2) 145 // specific items that jointly satisfy the restriction. 146 // We list all items explicitly rather than just giving their 147 // count, for robustness in the face of complex schema changes. 148 149 // A context class CX (which may be either abstract or concrete) 150 // has two exclusive concrete subtypes* C1, C2 if every concrete 151 // subtype* of CX is either C1 or C2. Note that if neither C1 or C2 152 // are equal to CX, then CX itself must be abstract. But it is 153 // also possible (for example) that C1 is CX (a concrete class) 154 // and C2 is a proper subtype of C1. 155 abstract_with_exclusive_concrete_subtypes_2, 156 157 // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}. 158 exclusive_concrete_methods_2, 159 160 // This dependency asserts that no instances of class or it's 161 // subclasses require finalization registration. 162 no_finalizable_subclasses, 163 164 // This dependency asserts when the CallSite.target value changed. 165 call_site_target_value, 166 167 TYPE_LIMIT 168 }; 169 enum { 170 LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT)) 171 172 // handy categorizations of dependency types: 173 all_types = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE), 174 175 non_klass_types = (1 << call_site_target_value), 176 klass_types = all_types & ~non_klass_types, 177 178 non_ctxk_types = (1 << evol_method) | (1 << call_site_target_value), 179 implicit_ctxk_types = 0, 180 explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types), 181 182 max_arg_count = 3, // current maximum number of arguments (incl. ctxk) 183 184 // A "context type" is a class or interface that 185 // provides context for evaluating a dependency. 186 // When present, it is one of the arguments (dep_context_arg). 187 // 188 // If a dependency does not have a context type, there is a 189 // default context, depending on the type of the dependency. 190 // This bit signals that a default context has been compressed away. 191 default_context_type_bit = (1<<LG2_TYPE_LIMIT) 192 }; 193 194 static const char* dep_name(DepType dept); 195 static int dep_args(DepType dept); 196 is_klass_type(DepType dept)197 static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); } 198 has_explicit_context_arg(DepType dept)199 static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); } has_implicit_context_arg(DepType dept)200 static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); } 201 dep_context_arg(DepType dept)202 static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; } dep_implicit_context_arg(DepType dept)203 static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; } 204 205 static void check_valid_dependency_type(DepType dept); 206 207 #if INCLUDE_JVMCI 208 // A Metadata* or object value recorded in an OopRecorder 209 class DepValue { 210 private: 211 // Unique identifier of the value within the associated OopRecorder that 212 // encodes both the category of the value (0: invalid, positive: metadata, negative: object) 213 // and the index within a category specific array (metadata: index + 1, object: -(index + 1)) 214 int _id; 215 216 public: DepValue()217 DepValue() : _id(0) {} DepValue(OopRecorder * rec,Metadata * metadata,DepValue * candidate=NULL)218 DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = NULL) { 219 assert(candidate == NULL || candidate->is_metadata(), "oops"); 220 if (candidate != NULL && candidate->as_metadata(rec) == metadata) { 221 _id = candidate->_id; 222 } else { 223 _id = rec->find_index(metadata) + 1; 224 } 225 } DepValue(OopRecorder * rec,jobject obj,DepValue * candidate=NULL)226 DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = NULL) { 227 assert(candidate == NULL || candidate->is_object(), "oops"); 228 if (candidate != NULL && candidate->as_object(rec) == obj) { 229 _id = candidate->_id; 230 } else { 231 _id = -(rec->find_index(obj) + 1); 232 } 233 } 234 235 // Used to sort values in ascending order of index() with metadata values preceding object values sort_key() const236 int sort_key() const { return -_id; } 237 operator ==(const DepValue & other) const238 bool operator == (const DepValue& other) const { return other._id == _id; } 239 is_valid() const240 bool is_valid() const { return _id != 0; } index() const241 int index() const { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; } is_metadata() const242 bool is_metadata() const { assert(is_valid(), "oops"); return _id > 0; } is_object() const243 bool is_object() const { assert(is_valid(), "oops"); return _id < 0; } 244 as_metadata(OopRecorder * rec) const245 Metadata* as_metadata(OopRecorder* rec) const { assert(is_metadata(), "oops"); return rec->metadata_at(index()); } as_klass(OopRecorder * rec) const246 Klass* as_klass(OopRecorder* rec) const { 247 Metadata* m = as_metadata(rec); 248 assert(m != NULL, "as_metadata returned NULL"); 249 assert(m->is_klass(), "oops"); 250 return (Klass*) m; 251 } as_method(OopRecorder * rec) const252 Method* as_method(OopRecorder* rec) const { 253 Metadata* m = as_metadata(rec); 254 assert(m != NULL, "as_metadata returned NULL"); 255 assert(m->is_method(), "oops"); 256 return (Method*) m; 257 } as_object(OopRecorder * rec) const258 jobject as_object(OopRecorder* rec) const { assert(is_object(), "oops"); return rec->oop_at(index()); } 259 }; 260 #endif // INCLUDE_JVMCI 261 262 private: 263 // State for writing a new set of dependencies: 264 GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept)) 265 GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT]; 266 #if INCLUDE_JVMCI 267 bool _using_dep_values; 268 GrowableArray<DepValue>* _dep_values[TYPE_LIMIT]; 269 #endif 270 271 static const char* _dep_name[TYPE_LIMIT]; 272 static int _dep_args[TYPE_LIMIT]; 273 dept_in_mask(DepType dept,int mask)274 static bool dept_in_mask(DepType dept, int mask) { 275 return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0; 276 } 277 note_dep_seen(int dept,ciBaseObject * x)278 bool note_dep_seen(int dept, ciBaseObject* x) { 279 assert(dept < BitsPerInt, "oob"); 280 int x_id = x->ident(); 281 assert(_dep_seen != NULL, "deps must be writable"); 282 int seen = _dep_seen->at_grow(x_id, 0); 283 _dep_seen->at_put(x_id, seen | (1<<dept)); 284 // return true if we've already seen dept/x 285 return (seen & (1<<dept)) != 0; 286 } 287 288 #if INCLUDE_JVMCI note_dep_seen(int dept,DepValue x)289 bool note_dep_seen(int dept, DepValue x) { 290 assert(dept < BitsPerInt, "oops"); 291 // place metadata deps at even indexes, object deps at odd indexes 292 int x_id = x.is_metadata() ? x.index() * 2 : (x.index() * 2) + 1; 293 assert(_dep_seen != NULL, "deps must be writable"); 294 int seen = _dep_seen->at_grow(x_id, 0); 295 _dep_seen->at_put(x_id, seen | (1<<dept)); 296 // return true if we've already seen dept/x 297 return (seen & (1<<dept)) != 0; 298 } 299 #endif 300 301 bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps, 302 int ctxk_i, ciKlass* ctxk); 303 #if INCLUDE_JVMCI 304 bool maybe_merge_ctxk(GrowableArray<DepValue>* deps, 305 int ctxk_i, DepValue ctxk); 306 #endif 307 308 void sort_all_deps(); 309 size_t estimate_size_in_bytes(); 310 311 // Initialize _deps, etc. 312 void initialize(ciEnv* env); 313 314 // State for making a new set of dependencies: 315 OopRecorder* _oop_recorder; 316 317 // Logging support 318 CompileLog* _log; 319 320 address _content_bytes; // everything but the oop references, encoded 321 size_t _size_in_bytes; 322 323 public: 324 // Make a new empty dependencies set. Dependencies(ciEnv * env)325 Dependencies(ciEnv* env) { 326 initialize(env); 327 } 328 #if INCLUDE_JVMCI 329 Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log); 330 #endif 331 332 private: 333 // Check for a valid context type. 334 // Enforce the restriction against array types. check_ctxk(ciKlass * ctxk)335 static void check_ctxk(ciKlass* ctxk) { 336 assert(ctxk->is_instance_klass(), "java types only"); 337 } check_ctxk_concrete(ciKlass * ctxk)338 static void check_ctxk_concrete(ciKlass* ctxk) { 339 assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete"); 340 } check_ctxk_abstract(ciKlass * ctxk)341 static void check_ctxk_abstract(ciKlass* ctxk) { 342 check_ctxk(ctxk); 343 assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract"); 344 } check_unique_method(ciKlass * ctxk,ciMethod * m)345 static void check_unique_method(ciKlass* ctxk, ciMethod* m) { 346 assert(!m->can_be_statically_bound(ctxk->as_instance_klass()), "redundant"); 347 } 348 349 void assert_common_1(DepType dept, ciBaseObject* x); 350 void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1); 351 void assert_common_3(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2); 352 353 public: 354 // Adding assertions to a new dependency set at compile time: 355 void assert_evol_method(ciMethod* m); 356 void assert_leaf_type(ciKlass* ctxk); 357 void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck); 358 void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk); 359 void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk); 360 void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm); 361 void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2); 362 void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2); 363 void assert_has_no_finalizable_subclasses(ciKlass* ctxk); 364 void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle); 365 366 #if INCLUDE_JVMCI 367 private: check_ctxk(Klass * ctxk)368 static void check_ctxk(Klass* ctxk) { 369 assert(ctxk->is_instance_klass(), "java types only"); 370 } check_ctxk_abstract(Klass * ctxk)371 static void check_ctxk_abstract(Klass* ctxk) { 372 check_ctxk(ctxk); 373 assert(ctxk->is_abstract(), "must be abstract"); 374 } check_unique_method(Klass * ctxk,Method * m)375 static void check_unique_method(Klass* ctxk, Method* m) { 376 assert(!m->can_be_statically_bound(InstanceKlass::cast(ctxk)), "redundant"); 377 } 378 379 void assert_common_1(DepType dept, DepValue x); 380 void assert_common_2(DepType dept, DepValue x0, DepValue x1); 381 382 public: 383 void assert_evol_method(Method* m); 384 void assert_has_no_finalizable_subclasses(Klass* ctxk); 385 void assert_leaf_type(Klass* ctxk); 386 void assert_unique_concrete_method(Klass* ctxk, Method* uniqm); 387 void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck); 388 void assert_call_site_target_value(oop callSite, oop methodHandle); 389 #endif // INCLUDE_JVMCI 390 391 // Define whether a given method or type is concrete. 392 // These methods define the term "concrete" as used in this module. 393 // For this module, an "abstract" class is one which is non-concrete. 394 // 395 // Future optimizations may allow some classes to remain 396 // non-concrete until their first instantiation, and allow some 397 // methods to remain non-concrete until their first invocation. 398 // In that case, there would be a middle ground between concrete 399 // and abstract (as defined by the Java language and VM). 400 static bool is_concrete_klass(Klass* k); // k is instantiable 401 static bool is_concrete_method(Method* m, Klass* k); // m is invocable 402 static Klass* find_finalizable_subclass(Klass* k); 403 404 // These versions of the concreteness queries work through the CI. 405 // The CI versions are allowed to skew sometimes from the VM 406 // (oop-based) versions. The cost of such a difference is a 407 // (safely) aborted compilation, or a deoptimization, or a missed 408 // optimization opportunity. 409 // 410 // In order to prevent spurious assertions, query results must 411 // remain stable within any single ciEnv instance. (I.e., they must 412 // not go back into the VM to get their value; they must cache the 413 // bit in the CI, either eagerly or lazily.) 414 static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable 415 static bool has_finalizable_subclass(ciInstanceKlass* k); 416 417 // As a general rule, it is OK to compile under the assumption that 418 // a given type or method is concrete, even if it at some future 419 // point becomes abstract. So dependency checking is one-sided, in 420 // that it permits supposedly concrete classes or methods to turn up 421 // as really abstract. (This shouldn't happen, except during class 422 // evolution, but that's the logic of the checking.) However, if a 423 // supposedly abstract class or method suddenly becomes concrete, a 424 // dependency on it must fail. 425 426 // Checking old assertions at run-time (in the VM only): 427 static Klass* check_evol_method(Method* m); 428 static Klass* check_leaf_type(Klass* ctxk); 429 static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck, 430 KlassDepChange* changes = NULL); 431 static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk, 432 KlassDepChange* changes = NULL); 433 static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk, 434 KlassDepChange* changes = NULL); 435 static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm, 436 KlassDepChange* changes = NULL); 437 static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2, 438 KlassDepChange* changes = NULL); 439 static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2, 440 KlassDepChange* changes = NULL); 441 static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL); 442 static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL); 443 // A returned Klass* is NULL if the dependency assertion is still 444 // valid. A non-NULL Klass* is a 'witness' to the assertion 445 // failure, a point in the class hierarchy where the assertion has 446 // been proven false. For example, if check_leaf_type returns 447 // non-NULL, the value is a subtype of the supposed leaf type. This 448 // witness value may be useful for logging the dependency failure. 449 // Note that, when a dependency fails, there may be several possible 450 // witnesses to the failure. The value returned from the check_foo 451 // method is chosen arbitrarily. 452 453 // The 'changes' value, if non-null, requests a limited spot-check 454 // near the indicated recent changes in the class hierarchy. 455 // It is used by DepStream::spot_check_dependency_at. 456 457 // Detecting possible new assertions: 458 static Klass* find_unique_concrete_subtype(Klass* ctxk); 459 static Method* find_unique_concrete_method(Klass* ctxk, Method* m); 460 static int find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]); 461 462 // Create the encoding which will be stored in an nmethod. 463 void encode_content_bytes(); 464 content_bytes()465 address content_bytes() { 466 assert(_content_bytes != NULL, "encode it first"); 467 return _content_bytes; 468 } size_in_bytes()469 size_t size_in_bytes() { 470 assert(_content_bytes != NULL, "encode it first"); 471 return _size_in_bytes; 472 } 473 oop_recorder()474 OopRecorder* oop_recorder() { return _oop_recorder; } log()475 CompileLog* log() { return _log; } 476 477 void copy_to(nmethod* nm); 478 479 DepType validate_dependencies(CompileTask* task, char** failure_detail = NULL); 480 481 void log_all_dependencies(); 482 log_dependency(DepType dept,GrowableArray<ciBaseObject * > * args)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 log_dependency(DepType dept,ciBaseObject * x0,ciBaseObject * x1=NULL,ciBaseObject * x2=NULL)491 void log_dependency(DepType dept, 492 ciBaseObject* x0, 493 ciBaseObject* x1 = NULL, 494 ciBaseObject* x2 = NULL) { 495 if (log() == NULL) { 496 return; 497 } 498 ResourceMark rm; 499 GrowableArray<ciBaseObject*>* ciargs = 500 new GrowableArray<ciBaseObject*>(dep_args(dept)); 501 assert (x0 != NULL, "no log x0"); 502 ciargs->push(x0); 503 504 if (x1 != NULL) { 505 ciargs->push(x1); 506 } 507 if (x2 != NULL) { 508 ciargs->push(x2); 509 } 510 assert(ciargs->length() == dep_args(dept), ""); 511 log_dependency(dept, ciargs); 512 } 513 514 class DepArgument : public ResourceObj { 515 private: 516 bool _is_oop; 517 bool _valid; 518 void* _value; 519 public: DepArgument()520 DepArgument() : _is_oop(false), _valid(false), _value(NULL) {} DepArgument(oop v)521 DepArgument(oop v): _is_oop(true), _valid(true), _value(v) {} DepArgument(Metadata * v)522 DepArgument(Metadata* v): _is_oop(false), _valid(true), _value(v) {} 523 is_null() const524 bool is_null() const { return _value == NULL; } is_oop() const525 bool is_oop() const { return _is_oop; } is_metadata() const526 bool is_metadata() const { return !_is_oop; } is_klass() const527 bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); } is_method() const528 bool is_method() const { return is_metadata() && metadata_value()->is_method(); } 529 oop_value() const530 oop oop_value() const { assert(_is_oop && _valid, "must be"); return (oop) _value; } metadata_value() const531 Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; } 532 }; 533 534 static void print_dependency(DepType dept, 535 GrowableArray<DepArgument>* args, 536 Klass* witness = NULL, outputStream* st = tty); 537 538 private: 539 // helper for encoding common context types as zero: 540 static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x); 541 542 static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x); 543 544 static void write_dependency_to(CompileLog* log, 545 DepType dept, 546 GrowableArray<ciBaseObject*>* args, 547 Klass* witness = NULL); 548 static void write_dependency_to(CompileLog* log, 549 DepType dept, 550 GrowableArray<DepArgument>* args, 551 Klass* witness = NULL); 552 static void write_dependency_to(xmlStream* xtty, 553 DepType dept, 554 GrowableArray<DepArgument>* args, 555 Klass* witness = NULL); 556 public: 557 // Use this to iterate over an nmethod's dependency set. 558 // Works on new and old dependency sets. 559 // Usage: 560 // 561 // ; 562 // Dependencies::DepType dept; 563 // for (Dependencies::DepStream deps(nm); deps.next(); ) { 564 // ... 565 // } 566 // 567 // The caller must be in the VM, since oops are not wrapped in handles. 568 class DepStream { 569 private: 570 nmethod* _code; // null if in a compiler thread 571 Dependencies* _deps; // null if not in a compiler thread 572 CompressedReadStream _bytes; 573 #ifdef ASSERT 574 size_t _byte_limit; 575 #endif 576 577 // iteration variables: 578 DepType _type; 579 int _xi[max_arg_count+1]; 580 581 void initial_asserts(size_t byte_limit) NOT_DEBUG({}); 582 583 inline Metadata* recorded_metadata_at(int i); 584 inline oop recorded_oop_at(int i); 585 586 Klass* check_klass_dependency(KlassDepChange* changes); 587 Klass* check_call_site_dependency(CallSiteDepChange* changes); 588 589 void trace_and_log_witness(Klass* witness); 590 591 public: DepStream(Dependencies * deps)592 DepStream(Dependencies* deps) 593 : _code(NULL), 594 _deps(deps), 595 _bytes(deps->content_bytes()) 596 { 597 initial_asserts(deps->size_in_bytes()); 598 } DepStream(nmethod * code)599 DepStream(nmethod* code) 600 : _code(code), 601 _deps(NULL), 602 _bytes(code->dependencies_begin()) 603 { 604 initial_asserts(code->dependencies_size()); 605 } 606 607 bool next(); 608 type()609 DepType type() { return _type; } is_oop_argument(int i)610 bool is_oop_argument(int i) { return type() == call_site_target_value; } 611 uintptr_t get_identifier(int i); 612 argument_count()613 int argument_count() { return dep_args(type()); } argument_index(int i)614 int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); 615 return _xi[i]; } 616 Metadata* argument(int i); // => recorded_oop_at(argument_index(i)) 617 oop argument_oop(int i); // => recorded_oop_at(argument_index(i)) 618 Klass* context_type(); 619 is_klass_type()620 bool is_klass_type() { return Dependencies::is_klass_type(type()); } 621 method_argument(int i)622 Method* method_argument(int i) { 623 Metadata* x = argument(i); 624 assert(x->is_method(), "type"); 625 return (Method*) x; 626 } type_argument(int i)627 Klass* type_argument(int i) { 628 Metadata* x = argument(i); 629 assert(x->is_klass(), "type"); 630 return (Klass*) x; 631 } 632 633 // The point of the whole exercise: Is this dep still OK? check_dependency()634 Klass* check_dependency() { 635 Klass* result = check_klass_dependency(NULL); 636 if (result != NULL) return result; 637 return check_call_site_dependency(NULL); 638 } 639 640 // A lighter version: Checks only around recent changes in a class 641 // hierarchy. (See Universe::flush_dependents_on.) 642 Klass* spot_check_dependency_at(DepChange& changes); 643 644 // Log the current dependency to xtty or compilation log. 645 void log_dependency(Klass* witness = NULL); 646 647 // Print the current dependency to tty. 648 void print_dependency(Klass* witness = NULL, bool verbose = false, outputStream* st = tty); 649 }; 650 friend class Dependencies::DepStream; 651 652 static void print_statistics() PRODUCT_RETURN; 653 }; 654 655 656 class DependencySignature : public ResourceObj { 657 private: 658 int _args_count; 659 uintptr_t _argument_hash[Dependencies::max_arg_count]; 660 Dependencies::DepType _type; 661 662 public: DependencySignature(Dependencies::DepStream & dep)663 DependencySignature(Dependencies::DepStream& dep) { 664 _args_count = dep.argument_count(); 665 _type = dep.type(); 666 for (int i = 0; i < _args_count; i++) { 667 _argument_hash[i] = dep.get_identifier(i); 668 } 669 } 670 671 static bool equals(DependencySignature const& s1, DependencySignature const& s2); hash(DependencySignature const & s1)672 static unsigned hash (DependencySignature const& s1) { return s1.arg(0) >> 2; } 673 args_count() const674 int args_count() const { return _args_count; } arg(int idx) const675 uintptr_t arg(int idx) const { return _argument_hash[idx]; } type() const676 Dependencies::DepType type() const { return _type; } 677 678 }; 679 680 681 // Every particular DepChange is a sub-class of this class. 682 class DepChange : public StackObj { 683 public: 684 // What kind of DepChange is this? is_klass_change() const685 virtual bool is_klass_change() const { return false; } is_call_site_change() const686 virtual bool is_call_site_change() const { return false; } 687 688 virtual void mark_for_deoptimization(nmethod* nm) = 0; 689 690 // Subclass casting with assertions. as_klass_change()691 KlassDepChange* as_klass_change() { 692 assert(is_klass_change(), "bad cast"); 693 return (KlassDepChange*) this; 694 } as_call_site_change()695 CallSiteDepChange* as_call_site_change() { 696 assert(is_call_site_change(), "bad cast"); 697 return (CallSiteDepChange*) this; 698 } 699 700 void print(); 701 702 public: 703 enum ChangeType { 704 NO_CHANGE = 0, // an uninvolved klass 705 Change_new_type, // a newly loaded type 706 Change_new_sub, // a super with a new subtype 707 Change_new_impl, // an interface with a new implementation 708 CHANGE_LIMIT, 709 Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream 710 }; 711 712 // Usage: 713 // for (DepChange::ContextStream str(changes); str.next(); ) { 714 // Klass* k = str.klass(); 715 // switch (str.change_type()) { 716 // ... 717 // } 718 // } 719 class ContextStream : public StackObj { 720 private: 721 DepChange& _changes; 722 friend class DepChange; 723 724 // iteration variables: 725 ChangeType _change_type; 726 Klass* _klass; 727 Array<InstanceKlass*>* _ti_base; // i.e., transitive_interfaces 728 int _ti_index; 729 int _ti_limit; 730 731 // start at the beginning: 732 void start(); 733 734 public: ContextStream(DepChange & changes)735 ContextStream(DepChange& changes) 736 : _changes(changes) 737 { start(); } 738 ContextStream(DepChange & changes,NoSafepointVerifier & nsv)739 ContextStream(DepChange& changes, NoSafepointVerifier& nsv) 740 : _changes(changes) 741 // the nsv argument makes it safe to hold oops like _klass 742 { start(); } 743 744 bool next(); 745 change_type()746 ChangeType change_type() { return _change_type; } klass()747 Klass* klass() { return _klass; } 748 }; 749 friend class DepChange::ContextStream; 750 }; 751 752 753 // A class hierarchy change coming through the VM (under the Compile_lock). 754 // The change is structured as a single new type with any number of supers 755 // and implemented interface types. Other than the new type, any of the 756 // super types can be context types for a relevant dependency, which the 757 // new type could invalidate. 758 class KlassDepChange : public DepChange { 759 private: 760 // each change set is rooted in exactly one new type (at present): 761 Klass* _new_type; 762 763 void initialize(); 764 765 public: 766 // notes the new type, marks it and all its super-types KlassDepChange(Klass * new_type)767 KlassDepChange(Klass* new_type) 768 : _new_type(new_type) 769 { 770 initialize(); 771 } 772 773 // cleans up the marks 774 ~KlassDepChange(); 775 776 // What kind of DepChange is this? is_klass_change() const777 virtual bool is_klass_change() const { return true; } 778 mark_for_deoptimization(nmethod * nm)779 virtual void mark_for_deoptimization(nmethod* nm) { 780 nm->mark_for_deoptimization(/*inc_recompile_counts=*/true); 781 } 782 new_type()783 Klass* new_type() { return _new_type; } 784 785 // involves_context(k) is true if k is new_type or any of the super types 786 bool involves_context(Klass* k); 787 }; 788 789 790 // A CallSite has changed its target. 791 class CallSiteDepChange : public DepChange { 792 private: 793 Handle _call_site; 794 Handle _method_handle; 795 796 public: 797 CallSiteDepChange(Handle call_site, Handle method_handle); 798 799 // What kind of DepChange is this? is_call_site_change() const800 virtual bool is_call_site_change() const { return true; } 801 mark_for_deoptimization(nmethod * nm)802 virtual void mark_for_deoptimization(nmethod* nm) { 803 nm->mark_for_deoptimization(/*inc_recompile_counts=*/false); 804 } 805 call_site() const806 oop call_site() const { return _call_site(); } method_handle() const807 oop method_handle() const { return _method_handle(); } 808 }; 809 810 #endif // SHARE_CODE_DEPENDENCIES_HPP 811