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