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