1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2018 SAP SE. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 #include "precompiled.hpp" 27 28 #include "classfile/classLoaderData.inline.hpp" 29 #include "classfile/classLoaderDataGraph.hpp" 30 #include "classfile/classLoaderHierarchyDCmd.hpp" 31 #include "memory/allocation.hpp" 32 #include "memory/resourceArea.hpp" 33 #include "runtime/safepoint.hpp" 34 #include "oops/reflectionAccessorImplKlassHelper.hpp" 35 #include "utilities/globalDefinitions.hpp" 36 #include "utilities/ostream.hpp" 37 38 39 ClassLoaderHierarchyDCmd::ClassLoaderHierarchyDCmd(outputStream* output, bool heap) 40 : DCmdWithParser(output, heap), 41 _show_classes("show-classes", "Print loaded classes.", "BOOLEAN", false, "false"), 42 _verbose("verbose", "Print detailed information.", "BOOLEAN", false, "false"), 43 _fold("fold", "Show loaders of the same name and class as one.", "BOOLEAN", true, "true") { 44 _dcmdparser.add_dcmd_option(&_show_classes); 45 _dcmdparser.add_dcmd_option(&_verbose); 46 _dcmdparser.add_dcmd_option(&_fold); 47 } 48 49 50 int ClassLoaderHierarchyDCmd::num_arguments() { 51 ResourceMark rm; 52 ClassLoaderHierarchyDCmd* dcmd = new ClassLoaderHierarchyDCmd(NULL, false); 53 if (dcmd != NULL) { 54 DCmdMark mark(dcmd); 55 return dcmd->_dcmdparser.num_arguments(); 56 } else { 57 return 0; 58 } 59 } 60 61 // Helper class for drawing the branches to the left of a node. 62 class BranchTracker : public StackObj { 63 // "<x>" 64 // " |---<y>" 65 // " | | 66 // " | <z>" 67 // " | |---<z1> 68 // " | |---<z2> 69 // ^^^^^^^ ^^^ 70 // A B 71 72 // Some terms for the graphics: 73 // - branch: vertical connection between a node's ancestor to a later sibling. 74 // - branchwork: (A) the string to print as a prefix at the start of each line, contains all branches. 75 // - twig (B): Length of the dashed line connecting a node to its branch. 76 // - branch spacing: how many spaces between branches are printed. 77 78 public: 79 80 enum { max_depth = 64, twig_len = 2, branch_spacing = 5 }; 81 82 private: 83 84 char _branches[max_depth]; 85 int _pos; 86 87 public: 88 BranchTracker() 89 : _pos(0) {} 90 91 void push(bool has_branch) { 92 if (_pos < max_depth) { 93 _branches[_pos] = has_branch ? '|' : ' '; 94 } 95 _pos ++; // beyond max depth, omit branch drawing but do count on. 96 } 97 98 void pop() { 99 assert(_pos > 0, "must be"); 100 _pos --; 101 } 102 103 void print(outputStream* st) { 104 for (int i = 0; i < _pos; i ++) { 105 st->print("%c%.*s", _branches[i], branch_spacing, " "); 106 } 107 } 108 109 class Mark { 110 BranchTracker& _tr; 111 public: 112 Mark(BranchTracker& tr, bool has_branch_here) 113 : _tr(tr) { _tr.push(has_branch_here); } 114 ~Mark() { _tr.pop(); } 115 }; 116 117 }; // end: BranchTracker 118 119 struct LoadedClassInfo : public ResourceObj { 120 public: 121 LoadedClassInfo* _next; 122 Klass* const _klass; 123 const ClassLoaderData* const _cld; 124 125 LoadedClassInfo(Klass* klass, const ClassLoaderData* cld) 126 : _klass(klass), _cld(cld) {} 127 128 }; 129 130 class LoaderTreeNode : public ResourceObj { 131 132 // We walk the CLDG and, for each CLD which is non-unsafe_anonymous, add 133 // a tree node. 134 // To add a node we need its parent node; if the parent node does not yet 135 // exist - because we have not yet encountered the CLD for the parent loader - 136 // we add a preliminary empty LoaderTreeNode for it. This preliminary node 137 // just contains the loader oop and nothing else. Once we encounter the CLD of 138 // this parent loader, we fill in all the other details. 139 140 const oop _loader_oop; 141 const ClassLoaderData* _cld; 142 143 LoaderTreeNode* _child; 144 LoaderTreeNode* _next; 145 146 LoadedClassInfo* _classes; 147 int _num_classes; 148 149 LoadedClassInfo* _anon_classes; 150 int _num_anon_classes; 151 152 // In default view, similar tree nodes (same loader class, same name or no name) 153 // are folded into each other to make the output more readable. 154 // _num_folded contains the number of nodes which have been folded into this 155 // one. 156 int _num_folded; 157 158 void print_with_childs(outputStream* st, BranchTracker& branchtracker, 159 bool print_classes, bool verbose) const { 160 161 ResourceMark rm; 162 163 if (_cld == NULL) { 164 // Not sure how this could happen: we added a preliminary node for a parent but then never encountered 165 // its CLD? 166 return; 167 } 168 169 // Retrieve information. 170 const Klass* const loader_klass = _cld->class_loader_klass(); 171 const Symbol* const loader_name = _cld->name(); 172 173 branchtracker.print(st); 174 175 // e.g. "+--- jdk.internal.reflect.DelegatingClassLoader" 176 st->print("+%.*s", BranchTracker::twig_len, "----------"); 177 if (_cld->is_the_null_class_loader_data()) { 178 st->print(" <bootstrap>"); 179 } else { 180 if (loader_name != NULL) { 181 st->print(" \"%s\",", loader_name->as_C_string()); 182 } 183 st->print(" %s", loader_klass != NULL ? loader_klass->external_name() : "??"); 184 if (_num_folded > 0) { 185 st->print(" (+ %d more)", _num_folded); 186 } 187 } 188 st->cr(); 189 190 // Output following this node (node details and child nodes) - up to the next sibling node 191 // needs to be prefixed with "|" if there is a follow up sibling. 192 const bool have_sibling = _next != NULL; 193 BranchTracker::Mark trm(branchtracker, have_sibling); 194 195 { 196 // optional node details following this node needs to be prefixed with "|" 197 // if there are follow up child nodes. 198 const bool have_child = _child != NULL; 199 BranchTracker::Mark trm(branchtracker, have_child); 200 201 // Empty line 202 branchtracker.print(st); 203 st->cr(); 204 205 const int indentation = 18; 206 207 if (verbose) { 208 branchtracker.print(st); 209 st->print_cr("%*s " PTR_FORMAT, indentation, "Loader Oop:", p2i(_loader_oop)); 210 branchtracker.print(st); 211 st->print_cr("%*s " PTR_FORMAT, indentation, "Loader Data:", p2i(_cld)); 212 branchtracker.print(st); 213 st->print_cr("%*s " PTR_FORMAT, indentation, "Loader Klass:", p2i(loader_klass)); 214 215 // Empty line 216 branchtracker.print(st); 217 st->cr(); 218 } 219 220 if (print_classes) { 221 if (_classes != NULL) { 222 for (LoadedClassInfo* lci = _classes; lci; lci = lci->_next) { 223 // Non-unsafe anonymous classes should live in the primary CLD of its loader 224 assert(lci->_cld == _cld, "must be"); 225 226 branchtracker.print(st); 227 if (lci == _classes) { // first iteration 228 st->print("%*s ", indentation, "Classes:"); 229 } else { 230 st->print("%*s ", indentation, ""); 231 } 232 st->print("%s", lci->_klass->external_name()); 233 234 // Special treatment for generated core reflection accessor classes: print invocation target. 235 if (ReflectionAccessorImplKlassHelper::is_generated_accessor(lci->_klass)) { 236 st->print(" (invokes: "); 237 ReflectionAccessorImplKlassHelper::print_invocation_target(st, lci->_klass); 238 st->print(")"); 239 } 240 241 st->cr(); 242 } 243 branchtracker.print(st); 244 st->print("%*s ", indentation, ""); 245 st->print_cr("(%u class%s)", _num_classes, (_num_classes == 1) ? "" : "es"); 246 247 // Empty line 248 branchtracker.print(st); 249 st->cr(); 250 } 251 252 if (_anon_classes != NULL) { 253 for (LoadedClassInfo* lci = _anon_classes; lci; lci = lci->_next) { 254 branchtracker.print(st); 255 if (lci == _anon_classes) { // first iteration 256 st->print("%*s ", indentation, "Unsafe Anonymous Classes:"); 257 } else { 258 st->print("%*s ", indentation, ""); 259 } 260 st->print("%s", lci->_klass->external_name()); 261 // For unsafe anonymous classes, also print CLD if verbose. Should be a different one than the primary CLD. 262 assert(lci->_cld != _cld, "must be"); 263 if (verbose) { 264 st->print(" (Loader Data: " PTR_FORMAT ")", p2i(lci->_cld)); 265 } 266 st->cr(); 267 } 268 branchtracker.print(st); 269 st->print("%*s ", indentation, ""); 270 st->print_cr("(%u unsafe anonymous class%s)", _num_anon_classes, (_num_anon_classes == 1) ? "" : "es"); 271 272 // Empty line 273 branchtracker.print(st); 274 st->cr(); 275 } 276 277 } // end: print_classes 278 279 } // Pop branchtracker mark 280 281 // Print children, recursively 282 LoaderTreeNode* c = _child; 283 while (c != NULL) { 284 c->print_with_childs(st, branchtracker, print_classes, verbose); 285 c = c->_next; 286 } 287 288 } 289 290 // Helper: Attempt to fold this node into the target node. If success, returns true. 291 // Folding can be done if both nodes are leaf nodes and they refer to the same loader class 292 // and they have the same name or no name (note: leaf check is done by caller). 293 bool can_fold_into(LoaderTreeNode* target_node) const { 294 assert(is_leaf() && target_node->is_leaf(), "must be leaf"); 295 return _cld->class_loader_klass() == target_node->_cld->class_loader_klass() && 296 _cld->name() == target_node->_cld->name(); 297 } 298 299 public: 300 301 LoaderTreeNode(const oop loader_oop) 302 : _loader_oop(loader_oop), _cld(NULL), _child(NULL), _next(NULL), 303 _classes(NULL), _num_classes(0), _anon_classes(NULL), _num_anon_classes(0), 304 _num_folded(0) 305 {} 306 307 void set_cld(const ClassLoaderData* cld) { 308 _cld = cld; 309 } 310 311 void add_child(LoaderTreeNode* info) { 312 info->_next = _child; 313 _child = info; 314 } 315 316 void add_sibling(LoaderTreeNode* info) { 317 assert(info->_next == NULL, "must be"); 318 info->_next = _next; 319 _next = info; 320 } 321 322 void add_classes(LoadedClassInfo* first_class, int num_classes, bool is_unsafe_anonymous) { 323 LoadedClassInfo** p_list_to_add_to = is_unsafe_anonymous ? &_anon_classes : &_classes; 324 // Search tail. 325 while ((*p_list_to_add_to) != NULL) { 326 p_list_to_add_to = &(*p_list_to_add_to)->_next; 327 } 328 *p_list_to_add_to = first_class; 329 if (is_unsafe_anonymous) { 330 _num_anon_classes += num_classes; 331 } else { 332 _num_classes += num_classes; 333 } 334 } 335 336 const ClassLoaderData* cld() const { 337 return _cld; 338 } 339 340 const oop loader_oop() const { 341 return _loader_oop; 342 } 343 344 LoaderTreeNode* find(const oop loader_oop) { 345 LoaderTreeNode* result = NULL; 346 if (_loader_oop == loader_oop) { 347 result = this; 348 } else { 349 LoaderTreeNode* c = _child; 350 while (c != NULL && result == NULL) { 351 result = c->find(loader_oop); 352 c = c->_next; 353 } 354 } 355 return result; 356 } 357 358 bool is_leaf() const { return _child == NULL; } 359 360 // Attempt to fold similar nodes among this node's children. We only fold leaf nodes 361 // (no child class loaders). 362 // For non-leaf nodes (class loaders with child class loaders), do this recursivly. 363 void fold_children() { 364 LoaderTreeNode* node = _child; 365 LoaderTreeNode* prev = NULL; 366 while (node != NULL) { 367 LoaderTreeNode* matching_node = NULL; 368 if (node->is_leaf()) { 369 // Look among the preceeding node siblings for a match. 370 for (LoaderTreeNode* node2 = _child; node2 != node && matching_node == NULL; 371 node2 = node2->_next) { 372 if (node2->is_leaf() && node->can_fold_into(node2)) { 373 matching_node = node2; 374 } 375 } 376 } else { 377 node->fold_children(); 378 } 379 if (matching_node != NULL) { 380 // Increase fold count for the matching node and remove folded node from the child list. 381 matching_node->_num_folded ++; 382 assert(prev != NULL, "Sanity"); // can never happen since we do not fold the first node. 383 prev->_next = node->_next; 384 } else { 385 prev = node; 386 } 387 node = node->_next; 388 } 389 } 390 391 void print_with_childs(outputStream* st, bool print_classes, bool print_add_info) const { 392 BranchTracker bwt; 393 print_with_childs(st, bwt, print_classes, print_add_info); 394 } 395 396 }; 397 398 class LoadedClassCollectClosure : public KlassClosure { 399 public: 400 LoadedClassInfo* _list; 401 const ClassLoaderData* _cld; 402 int _num_classes; 403 LoadedClassCollectClosure(const ClassLoaderData* cld) 404 : _list(NULL), _cld(cld), _num_classes(0) {} 405 void do_klass(Klass* k) { 406 LoadedClassInfo* lki = new LoadedClassInfo(k, _cld); 407 lki->_next = _list; 408 _list = lki; 409 _num_classes ++; 410 } 411 }; 412 413 class LoaderInfoScanClosure : public CLDClosure { 414 415 const bool _print_classes; 416 const bool _verbose; 417 LoaderTreeNode* _root; 418 419 static void fill_in_classes(LoaderTreeNode* info, const ClassLoaderData* cld) { 420 assert(info != NULL && cld != NULL, "must be"); 421 LoadedClassCollectClosure lccc(cld); 422 const_cast<ClassLoaderData*>(cld)->classes_do(&lccc); 423 if (lccc._num_classes > 0) { 424 info->add_classes(lccc._list, lccc._num_classes, cld->is_unsafe_anonymous()); 425 } 426 } 427 428 LoaderTreeNode* find_node_or_add_empty_node(oop loader_oop) { 429 430 assert(_root != NULL, "root node must exist"); 431 432 if (loader_oop == NULL) { 433 return _root; 434 } 435 436 // Check if a node for this oop already exists. 437 LoaderTreeNode* info = _root->find(loader_oop); 438 439 if (info == NULL) { 440 // It does not. Create a node. 441 info = new LoaderTreeNode(loader_oop); 442 443 // Add it to tree. 444 LoaderTreeNode* parent_info = NULL; 445 446 // Recursively add parent nodes if needed. 447 const oop parent_oop = java_lang_ClassLoader::parent(loader_oop); 448 if (parent_oop == NULL) { 449 parent_info = _root; 450 } else { 451 parent_info = find_node_or_add_empty_node(parent_oop); 452 } 453 assert(parent_info != NULL, "must be"); 454 455 parent_info->add_child(info); 456 } 457 return info; 458 } 459 460 461 public: 462 LoaderInfoScanClosure(bool print_classes, bool verbose) 463 : _print_classes(print_classes), _verbose(verbose), _root(NULL) { 464 _root = new LoaderTreeNode(NULL); 465 } 466 467 void print_results(outputStream* st) const { 468 _root->print_with_childs(st, _print_classes, _verbose); 469 } 470 471 void do_cld (ClassLoaderData* cld) { 472 473 // We do not display unloading loaders, for now. 474 if (!cld->is_alive()) { 475 return; 476 } 477 478 const oop loader_oop = cld->class_loader(); 479 480 LoaderTreeNode* info = find_node_or_add_empty_node(loader_oop); 481 assert(info != NULL, "must be"); 482 483 // Update CLD in node, but only if this is the primary CLD for this loader. 484 if (cld->is_unsafe_anonymous() == false) { 485 assert(info->cld() == NULL, "there should be only one primary CLD per loader"); 486 info->set_cld(cld); 487 } 488 489 // Add classes. 490 fill_in_classes(info, cld); 491 } 492 493 void fold() { 494 _root->fold_children(); 495 } 496 497 }; 498 499 500 class ClassLoaderHierarchyVMOperation : public VM_Operation { 501 outputStream* const _out; 502 const bool _show_classes; 503 const bool _verbose; 504 const bool _fold; 505 public: 506 ClassLoaderHierarchyVMOperation(outputStream* out, bool show_classes, bool verbose, bool fold) : 507 _out(out), _show_classes(show_classes), _verbose(verbose), _fold(fold) 508 {} 509 510 VMOp_Type type() const { 511 return VMOp_ClassLoaderHierarchyOperation; 512 } 513 514 void doit() { 515 assert(SafepointSynchronize::is_at_safepoint(), "must be a safepoint"); 516 ResourceMark rm; 517 LoaderInfoScanClosure cl (_show_classes, _verbose); 518 ClassLoaderDataGraph::cld_do(&cl); 519 // In non-verbose and non-show-classes mode, attempt to fold the tree. 520 if (_fold) { 521 if (!_verbose && !_show_classes) { 522 cl.fold(); 523 } 524 } 525 cl.print_results(_out); 526 } 527 }; 528 529 // This command needs to be executed at a safepoint. 530 void ClassLoaderHierarchyDCmd::execute(DCmdSource source, TRAPS) { 531 ClassLoaderHierarchyVMOperation op(output(), _show_classes.value(), _verbose.value(), _fold.value()); 532 VMThread::execute(&op); 533 }