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
39ClassLoaderHierarchyDCmd::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
50int 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.
62class 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
78public:
79
80 enum { max_depth = 64, twig_len = 2, branch_spacing = 5 };
81
82private:
83
84 char _branches[max_depth];
85 int _pos;
86
87public:
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
119struct LoadedClassInfo : public ResourceObj {
120public:
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
130class 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
299public:
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
398class LoadedClassCollectClosure : public KlassClosure {
399public:
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
413class 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
461public:
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
500class ClassLoaderHierarchyVMOperation : public VM_Operation {
501 outputStream* const _out;
502 const bool _show_classes;
503 const bool _verbose;
504 const bool _fold;
505public:
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::loaded_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.
530void ClassLoaderHierarchyDCmd::execute(DCmdSource source, TRAPS) {
531 ClassLoaderHierarchyVMOperation op(output(), _show_classes.value(), _verbose.value(), _fold.value());
532 VMThread::execute(&op);
533}
534