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