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
161 branchtracker.print(st);
162
163 // e.g. "+-- jdk.internal.reflect.DelegatingClassLoader @<id>, jdk.internal.reflect.DelegatingClassLoader {0x<address of loader oop>}"
164 st->print("+%.*s", BranchTracker::twig_len, "----------");
165 st->print(" %s,", _cld->loader_name_and_id());
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 if (_classes != NULL) {
202 for (LoadedClassInfo* lci = _classes; lci; lci = lci->_next) {
203 // Non-anonymous classes should live in the primary CLD of its loader
204 assert(lci->_cld == _cld, "must be");
205
206 branchtracker.print(st);
207 if (lci == _classes) { // first iteration
208 st->print("%*s ", indentation, "Classes:");
209 } else {
210 st->print("%*s ", indentation, "");
211 }
212 st->print("%s", lci->_klass->external_name());
213
214 // Special treatment for generated core reflection accessor classes: print invocation target.
215 if (ReflectionAccessorImplKlassHelper::is_generated_accessor(lci->_klass)) {
216 st->print(" (invokes: ");
217 ReflectionAccessorImplKlassHelper::print_invocation_target(st, lci->_klass);
218 st->print(")");
219 }
220
221 st->cr();
222 }
223 branchtracker.print(st);
224 st->print("%*s ", indentation, "");
225 st->print_cr("(%u class%s)", _num_classes, (_num_classes == 1) ? "" : "es");
226
227 // Empty line
228 branchtracker.print(st);
229 st->cr();
230 }
231
232 if (_anon_classes != NULL) {
233 for (LoadedClassInfo* lci = _anon_classes; lci; lci = lci->_next) {
234 branchtracker.print(st);
235 if (lci == _anon_classes) { // first iteration
236 st->print("%*s ", indentation, "Anonymous Classes:");
237 } else {
238 st->print("%*s ", indentation, "");
239 }
240 st->print("%s", lci->_klass->external_name());
241 // For anonymous classes, also print CLD if verbose. Should be a different one than the primary CLD.
242 assert(lci->_cld != _cld, "must be");
243 if (verbose) {
244 st->print(" (CLD: " PTR_FORMAT ")", p2i(lci->_cld));
245 }
246 st->cr();
247 }
248 branchtracker.print(st);
249 st->print("%*s ", indentation, "");
250 st->print_cr("(%u anonymous class%s)", _num_anon_classes, (_num_anon_classes == 1) ? "" : "es");
251
252 // Empty line
253 branchtracker.print(st);
254 st->cr();
255 }
256
257 } // end: print_classes
258
259 } // Pop branchtracker mark
260
261 // Print children, recursively
262 LoaderTreeNode* c = _child;
263 while (c != NULL) {
264 c->print_with_childs(st, branchtracker, print_classes, verbose);
265 c = c->_next;
266 }
267
268 }
269
270 public:
271
272 LoaderTreeNode(const oop loader_oop)
273 : _loader_oop(loader_oop), _cld(NULL)
274 , _child(NULL), _next(NULL)
275 , _classes(NULL), _anon_classes(NULL)
276 , _num_classes(0), _num_anon_classes(0) {}
277
278 void set_cld(const ClassLoaderData* cld) {
279 _cld = cld;
280 }
281
282 void add_child(LoaderTreeNode* info) {
283 info->_next = _child;
284 _child = info;
285 }
286
287 void add_sibling(LoaderTreeNode* info) {
288 assert(info->_next == NULL, "must be");
289 info->_next = _next;
290 _next = info;
291 }
292
293 void add_classes(LoadedClassInfo* first_class, int num_classes, bool anonymous) {
294 LoadedClassInfo** p_list_to_add_to = anonymous ? &_anon_classes : &_classes;
295 // Search tail.
296 while ((*p_list_to_add_to) != NULL) {
297 p_list_to_add_to = &(*p_list_to_add_to)->_next;
298 }
299 *p_list_to_add_to = first_class;
300 if (anonymous) {
301 _num_anon_classes += num_classes;
302 } else {
303 _num_classes += num_classes;
304 }
305 }
306
307 const ClassLoaderData* cld() const {
308 return _cld;
309 }
310
311 const oop loader_oop() const {
312 return _loader_oop;
313 }
314
315 LoaderTreeNode* find(const oop loader_oop) {
316 LoaderTreeNode* result = NULL;
317 if (_loader_oop == loader_oop) {
318 result = this;
319 } else {
320 LoaderTreeNode* c = _child;
321 while (c != NULL && result == NULL) {
322 result = c->find(loader_oop);
323 c = c->_next;
324 }
325 }
326 return result;
327 }
328
329 void print_with_childs(outputStream* st, bool print_classes, bool print_add_info) const {
330 BranchTracker bwt;
331 print_with_childs(st, bwt, print_classes, print_add_info);
332 }
333
334 };
335
336 class LoadedClassCollectClosure : public KlassClosure {
337 public:
338 LoadedClassInfo* _list;
339 const ClassLoaderData* _cld;
340 int _num_classes;
341 LoadedClassCollectClosure(const ClassLoaderData* cld)
342 : _list(NULL), _cld(cld), _num_classes(0) {}
343 void do_klass(Klass* k) {
344 LoadedClassInfo* lki = new LoadedClassInfo(k, _cld);
345 lki->_next = _list;
346 _list = lki;
347 _num_classes ++;
348 }
349 };
350
351 class LoaderInfoScanClosure : public CLDClosure {
352
353 const bool _print_classes;
354 const bool _verbose;
355 LoaderTreeNode* _root;
356
357 static void fill_in_classes(LoaderTreeNode* info, const ClassLoaderData* cld) {
358 assert(info != NULL && cld != NULL, "must be");
359 LoadedClassCollectClosure lccc(cld);
360 const_cast<ClassLoaderData*>(cld)->classes_do(&lccc);
361 if (lccc._num_classes > 0) {
362 info->add_classes(lccc._list, lccc._num_classes, cld->is_anonymous());
363 }
364 }
365
366 LoaderTreeNode* find_node_or_add_empty_node(oop loader_oop) {
367
368 assert(_root != NULL, "root node must exist");
369
370 if (loader_oop == NULL) {
371 return _root;
372 }
373
374 // Check if a node for this oop already exists.
375 LoaderTreeNode* info = _root->find(loader_oop);
376
377 if (info == NULL) {
378 // It does not. Create a node.
379 info = new LoaderTreeNode(loader_oop);
380
381 // Add it to tree.
382 LoaderTreeNode* parent_info = NULL;
383
384 // Recursively add parent nodes if needed.
385 const oop parent_oop = java_lang_ClassLoader::parent(loader_oop);
386 if (parent_oop == NULL) {
387 parent_info = _root;
388 } else {
389 parent_info = find_node_or_add_empty_node(parent_oop);
390 }
391 assert(parent_info != NULL, "must be");
392
393 parent_info->add_child(info);
394 }
395 return info;
396 }
397
398
399 public:
400 LoaderInfoScanClosure(bool print_classes, bool verbose)
401 : _print_classes(print_classes), _verbose(verbose), _root(NULL) {
402 _root = new LoaderTreeNode(NULL);
403 }
404
405 void print_results(outputStream* st) const {
406 _root->print_with_childs(st, _print_classes, _verbose);
407 }
408
409 void do_cld (ClassLoaderData* cld) {
410
411 // We do not display unloading loaders, for now.
412 if (cld->is_unloading()) {
413 return;
414 }
415
416 const oop loader_oop = cld->class_loader();
417
418 LoaderTreeNode* info = find_node_or_add_empty_node(loader_oop);
419 assert(info != NULL, "must be");
420
421 // Update CLD in node, but only if this is the primary CLD for this loader.
422 if (cld->is_anonymous() == false) {
423 assert(info->cld() == NULL, "there should be only one primary CLD per loader");
424 info->set_cld(cld);
425 }
426
427 // Add classes.
428 fill_in_classes(info, cld);
429 }
430
431 };
432
433
434 class ClassLoaderHierarchyVMOperation : public VM_Operation {
435 outputStream* const _out;
436 const bool _show_classes;
437 const bool _verbose;
438 public:
439 ClassLoaderHierarchyVMOperation(outputStream* out, bool show_classes, bool verbose) :
440 _out(out), _show_classes(show_classes), _verbose(verbose)
441 {}
442
443 VMOp_Type type() const {
444 return VMOp_ClassLoaderHierarchyOperation;
445 }
446
447 void doit() {
448 assert(SafepointSynchronize::is_at_safepoint(), "must be a safepoint");
449 ResourceMark rm;
450 LoaderInfoScanClosure cl (_show_classes, _verbose);
451 ClassLoaderDataGraph::cld_do(&cl);
452 cl.print_results(_out);
453 }
454 };
455
456 // This command needs to be executed at a safepoint.
457 void ClassLoaderHierarchyDCmd::execute(DCmdSource source, TRAPS) {
458 ClassLoaderHierarchyVMOperation op(output(), _show_classes.value(), _verbose.value());
459 VMThread::execute(&op);
460 }