19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotClassInitializer.hpp"
26 #include "cds/archiveBuilder.hpp"
27 #include "cds/cdsHeapVerifier.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionaryShared.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "logging/log.hpp"
34 #include "logging/logStream.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/fieldStreams.inline.hpp"
37 #include "oops/klass.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/fieldDescriptor.inline.hpp"
40
41 #if INCLUDE_CDS_JAVA_HEAP
42
43 // CDSHeapVerifier is used to check for problems where an archived object references a
44 // static field that may be get a different value at runtime.
45 //
46 // *Please see comments in aotClassInitializer.cpp for how to avoid such problems*,
47 //
48 // In the following example,
49 // Foo.get.test()
50 // correctly returns true when CDS disabled, but incorrectly returns false when CDS is enabled,
51 // because the archived archivedFoo.bar value is different than Bar.bar.
52 //
53 // class Foo {
54 // static final Foo archivedFoo; // this field is archived by CDS
55 // Bar bar;
56 // static {
57 // CDS.initializeFromArchive(Foo.class);
58 // if (archivedFoo == null) {
82 // [A] In most of the cases, the module bootstrap code will update the static field
83 // to point to part of the archived module graph. E.g.,
84 // - java/lang/System::bootLayer
85 // - jdk/internal/loader/ClassLoaders::BOOT_LOADER
86 // [B] A final static String that's explicitly initialized inside <clinit>, but
87 // its value is deterministic and is always the same string literal.
88 // [C] A non-final static string that is assigned a string literal during class
89 // initialization; this string is never changed during -Xshare:dump.
90 // [D] Simple caches whose value doesn't matter.
91 // [E] Other cases (see comments in-line below).
92
93 CDSHeapVerifier::CDSHeapVerifier() : _archived_objs(0), _problems(0)
94 {
95 # define ADD_EXCL(...) { static const char* e[] = {__VA_ARGS__, nullptr}; add_exclusion(e); }
96
97 // Unfortunately this needs to be manually maintained. If
98 // test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchivedEnumTest.java fails,
99 // you might need to fix the core library code, or fix the ADD_EXCL entries below.
100 //
101 // class field type
102 ADD_EXCL("java/lang/ClassLoader", "scl"); // A
103 ADD_EXCL("java/lang/Module", "ALL_UNNAMED_MODULE", // A
104 "ALL_UNNAMED_MODULE_SET", // A
105 "EVERYONE_MODULE", // A
106 "EVERYONE_SET"); // A
107
108 // This is the same as java/util/ImmutableCollections::EMPTY_SET, which is archived
109 ADD_EXCL("java/lang/reflect/AccessFlag$Location", "EMPTY_SET"); // E
110
111 ADD_EXCL("java/lang/System", "bootLayer"); // A
112
113 ADD_EXCL("java/util/Collections", "EMPTY_LIST"); // E
114
115 // A dummy object used by HashSet. The value doesn't matter and it's never
116 // tested for equality.
117 ADD_EXCL("java/util/HashSet", "PRESENT"); // E
118 ADD_EXCL("jdk/internal/loader/BuiltinClassLoader", "packageToModule"); // A
119 ADD_EXCL("jdk/internal/loader/ClassLoaders", "BOOT_LOADER", // A
120 "APP_LOADER", // A
121 "PLATFORM_LOADER"); // A
122 ADD_EXCL("jdk/internal/module/Builder", "cachedVersion"); // D
127 ADD_EXCL("jdk/internal/module/ServicesCatalog", "CLV"); // A
128
129 // This just points to an empty Map
130 ADD_EXCL("jdk/internal/reflect/Reflection", "methodFilterMap"); // E
131
132 // Integer for 0 and 1 are in java/lang/Integer$IntegerCache and are archived
133 ADD_EXCL("sun/invoke/util/ValueConversions", "ONE_INT", // E
134 "ZERO_INT"); // E
135
136 if (CDSConfig::is_dumping_method_handles()) {
137 ADD_EXCL("java/lang/invoke/InvokerBytecodeGenerator", "MEMBERNAME_FACTORY", // D
138 "CD_Object_array", // E same as <...>ConstantUtils.CD_Object_array::CD_Object
139 "INVOKER_SUPER_DESC"); // E same as java.lang.constant.ConstantDescs::CD_Object
140
141 ADD_EXCL("java/lang/runtime/ObjectMethods", "CLASS_IS_INSTANCE", // D
142 "FALSE", // D
143 "TRUE", // D
144 "ZERO"); // D
145 }
146
147 # undef ADD_EXCL
148
149 ClassLoaderDataGraph::classes_do(this);
150 }
151
152 CDSHeapVerifier::~CDSHeapVerifier() {
153 if (_problems > 0) {
154 log_error(aot, heap)("Scanned %d objects. Found %d case(s) where "
155 "an object points to a static field that "
156 "may hold a different value at runtime.", _archived_objs, _problems);
157 log_error(aot, heap)("Please see cdsHeapVerifier.cpp and aotClassInitializer.cpp for details");
158 MetaspaceShared::unrecoverable_writing_error();
159 }
160 }
161
162 class CDSHeapVerifier::CheckStaticFields : public FieldClosure {
163 CDSHeapVerifier* _verifier;
164 InstanceKlass* _ik; // The class whose static fields are being checked.
165 const char** _exclusions;
166 public:
254 }
255
256 if (ArchiveUtils::has_aot_initialized_mirror(ik)) {
257 // ik's <clinit> won't be executed at runtime, the static fields in
258 // ik will carry their values to runtime.
259 return;
260 }
261
262 CheckStaticFields csf(this, ik);
263 ik->do_local_static_fields(&csf);
264 }
265 }
266
267 void CDSHeapVerifier::add_static_obj_field(InstanceKlass* ik, oop field, Symbol* name) {
268 StaticFieldInfo info = {ik, name};
269 _table.put(field, info);
270 }
271
272 // This function is called once for every archived heap object. Warn if this object is referenced by
273 // a static field of a class that's not aot-initialized.
274 inline bool CDSHeapVerifier::do_entry(oop& orig_obj, HeapShared::CachedOopInfo& value) {
275 _archived_objs++;
276
277 if (java_lang_String::is_instance(orig_obj) && HeapShared::is_dumped_interned_string(orig_obj)) {
278 // It's quite often for static fields to have interned strings. These are most likely not
279 // problematic (and are hard to filter). So we will ignore them.
280 return true; /* keep on iterating */
281 }
282
283 StaticFieldInfo* info = _table.get(orig_obj);
284 if (info != nullptr) {
285 ResourceMark rm;
286 char* class_name = info->_holder->name()->as_C_string();
287 char* field_name = info->_name->as_C_string();
288 LogStream ls(Log(aot, heap)::warning());
289 ls.print_cr("Archive heap points to a static field that may hold a different value at runtime:");
290 ls.print_cr("Field: %s::%s", class_name, field_name);
291 ls.print("Value: ");
292 orig_obj->print_on(&ls);
293 ls.print_cr("--- trace begin ---");
294 trace_to_root(&ls, orig_obj, nullptr, &value);
304 oop _orig_obj;
305 oop _orig_field;
306 outputStream* _st;
307
308 public:
309 TraceFields(oop orig_obj, oop orig_field, outputStream* st)
310 : _orig_obj(orig_obj), _orig_field(orig_field), _st(st) {}
311
312 void do_field(fieldDescriptor* fd) {
313 if (fd->field_type() == T_OBJECT || fd->field_type() == T_ARRAY) {
314 oop obj_field = _orig_obj->obj_field(fd->offset());
315 if (obj_field == _orig_field) {
316 _st->print("::%s (offset = %d)", fd->name()->as_C_string(), fd->offset());
317 }
318 }
319 }
320 };
321
322 // Call this function (from gdb, etc) if you want to know why an object is archived.
323 void CDSHeapVerifier::trace_to_root(outputStream* st, oop orig_obj) {
324 HeapShared::CachedOopInfo* info = HeapShared::archived_object_cache()->get(orig_obj);
325 if (info != nullptr) {
326 trace_to_root(st, orig_obj, nullptr, info);
327 } else {
328 st->print_cr("Not an archived object??");
329 }
330 }
331
332 const char* static_field_name(oop mirror, oop field) {
333 Klass* k = java_lang_Class::as_Klass(mirror);
334 if (k->is_instance_klass()) {
335 for (JavaFieldStream fs(InstanceKlass::cast(k)); !fs.done(); fs.next()) {
336 if (fs.access_flags().is_static()) {
337 fieldDescriptor& fd = fs.field_descriptor();
338 switch (fd.field_type()) {
339 case T_OBJECT:
340 case T_ARRAY:
341 if (mirror->obj_field(fd.offset()) == field) {
342 return fs.name()->as_C_string();
343 }
344 break;
345 default:
346 break;
347 }
348 }
349 }
350 }
351
352 return "<unknown>";
353 }
354
355 int CDSHeapVerifier::trace_to_root(outputStream* st, oop orig_obj, oop orig_field, HeapShared::CachedOopInfo* info) {
356 int level = 0;
357 if (info->orig_referrer() != nullptr) {
358 HeapShared::CachedOopInfo* ref = HeapShared::archived_object_cache()->get(info->orig_referrer());
359 assert(ref != nullptr, "sanity");
360 level = trace_to_root(st, info->orig_referrer(), orig_obj, ref) + 1;
361 } else if (java_lang_String::is_instance(orig_obj)) {
362 st->print_cr("[%2d] (shared string table)", level++);
363 }
364 Klass* k = orig_obj->klass();
365 ResourceMark rm;
366 st->print("[%2d] ", level);
367 orig_obj->print_address_on(st);
368 st->print(" %s", k->internal_name());
369 if (java_lang_Class::is_instance(orig_obj)) {
370 st->print(" (%s::%s)", java_lang_Class::as_Klass(orig_obj)->external_name(), static_field_name(orig_obj, orig_field));
371 }
372 if (orig_field != nullptr) {
373 if (k->is_instance_klass()) {
374 TraceFields clo(orig_obj, orig_field, st);
375 InstanceKlass::cast(k)->do_nonstatic_fields(&clo);
376 } else {
377 assert(orig_obj->is_objArray(), "must be");
378 objArrayOop array = (objArrayOop)orig_obj;
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotClassInitializer.hpp"
26 #include "cds/archiveBuilder.hpp"
27 #include "cds/cdsHeapVerifier.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/moduleEntry.hpp"
31 #include "classfile/systemDictionaryShared.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "logging/log.hpp"
34 #include "logging/logStream.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/fieldStreams.inline.hpp"
37 #include "oops/klass.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "oops/oopHandle.inline.hpp"
40 #include "runtime/fieldDescriptor.inline.hpp"
41
42 #if INCLUDE_CDS_JAVA_HEAP
43
44 // CDSHeapVerifier is used to check for problems where an archived object references a
45 // static field that may be get a different value at runtime.
46 //
47 // *Please see comments in aotClassInitializer.cpp for how to avoid such problems*,
48 //
49 // In the following example,
50 // Foo.get.test()
51 // correctly returns true when CDS disabled, but incorrectly returns false when CDS is enabled,
52 // because the archived archivedFoo.bar value is different than Bar.bar.
53 //
54 // class Foo {
55 // static final Foo archivedFoo; // this field is archived by CDS
56 // Bar bar;
57 // static {
58 // CDS.initializeFromArchive(Foo.class);
59 // if (archivedFoo == null) {
83 // [A] In most of the cases, the module bootstrap code will update the static field
84 // to point to part of the archived module graph. E.g.,
85 // - java/lang/System::bootLayer
86 // - jdk/internal/loader/ClassLoaders::BOOT_LOADER
87 // [B] A final static String that's explicitly initialized inside <clinit>, but
88 // its value is deterministic and is always the same string literal.
89 // [C] A non-final static string that is assigned a string literal during class
90 // initialization; this string is never changed during -Xshare:dump.
91 // [D] Simple caches whose value doesn't matter.
92 // [E] Other cases (see comments in-line below).
93
94 CDSHeapVerifier::CDSHeapVerifier() : _archived_objs(0), _problems(0)
95 {
96 # define ADD_EXCL(...) { static const char* e[] = {__VA_ARGS__, nullptr}; add_exclusion(e); }
97
98 // Unfortunately this needs to be manually maintained. If
99 // test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchivedEnumTest.java fails,
100 // you might need to fix the core library code, or fix the ADD_EXCL entries below.
101 //
102 // class field type
103 ADD_EXCL("java/lang/ClassLoader$Holder", "scl"); // A
104 ADD_EXCL("java/lang/Module", "ALL_UNNAMED_MODULE", // A
105 "ALL_UNNAMED_MODULE_SET", // A
106 "EVERYONE_MODULE", // A
107 "EVERYONE_SET"); // A
108
109 // This is the same as java/util/ImmutableCollections::EMPTY_SET, which is archived
110 ADD_EXCL("java/lang/reflect/AccessFlag$Location", "EMPTY_SET"); // E
111
112 ADD_EXCL("java/lang/System", "bootLayer"); // A
113
114 ADD_EXCL("java/util/Collections", "EMPTY_LIST"); // E
115
116 // A dummy object used by HashSet. The value doesn't matter and it's never
117 // tested for equality.
118 ADD_EXCL("java/util/HashSet", "PRESENT"); // E
119 ADD_EXCL("jdk/internal/loader/BuiltinClassLoader", "packageToModule"); // A
120 ADD_EXCL("jdk/internal/loader/ClassLoaders", "BOOT_LOADER", // A
121 "APP_LOADER", // A
122 "PLATFORM_LOADER"); // A
123 ADD_EXCL("jdk/internal/module/Builder", "cachedVersion"); // D
128 ADD_EXCL("jdk/internal/module/ServicesCatalog", "CLV"); // A
129
130 // This just points to an empty Map
131 ADD_EXCL("jdk/internal/reflect/Reflection", "methodFilterMap"); // E
132
133 // Integer for 0 and 1 are in java/lang/Integer$IntegerCache and are archived
134 ADD_EXCL("sun/invoke/util/ValueConversions", "ONE_INT", // E
135 "ZERO_INT"); // E
136
137 if (CDSConfig::is_dumping_method_handles()) {
138 ADD_EXCL("java/lang/invoke/InvokerBytecodeGenerator", "MEMBERNAME_FACTORY", // D
139 "CD_Object_array", // E same as <...>ConstantUtils.CD_Object_array::CD_Object
140 "INVOKER_SUPER_DESC"); // E same as java.lang.constant.ConstantDescs::CD_Object
141
142 ADD_EXCL("java/lang/runtime/ObjectMethods", "CLASS_IS_INSTANCE", // D
143 "FALSE", // D
144 "TRUE", // D
145 "ZERO"); // D
146 }
147
148 if (CDSConfig::is_dumping_packages()) {
149 ADD_EXCL("java/lang/Package$VersionInfo", "NULL_VERSION_INFO"); // D
150 }
151
152 if (CDSConfig::is_dumping_dynamic_proxies()) {
153 ADD_EXCL("java/lang/reflect/ProxyGenerator", "CD_Object_array"); // D
154 }
155
156 // These are used by BuiltinClassLoader::negativeLookupCache, etc but seem to be
157 // OK. TODO - we should completely disable the caching unless ArchiveLoaderLookupCache
158 // is enabled
159 ADD_EXCL("java/lang/Boolean", "TRUE", // E
160 "FALSE"); // E
161
162 # undef ADD_EXCL
163
164 ClassLoaderDataGraph::classes_do(this);
165 }
166
167 CDSHeapVerifier::~CDSHeapVerifier() {
168 if (_problems > 0) {
169 log_error(aot, heap)("Scanned %d objects. Found %d case(s) where "
170 "an object points to a static field that "
171 "may hold a different value at runtime.", _archived_objs, _problems);
172 log_error(aot, heap)("Please see cdsHeapVerifier.cpp and aotClassInitializer.cpp for details");
173 MetaspaceShared::unrecoverable_writing_error();
174 }
175 }
176
177 class CDSHeapVerifier::CheckStaticFields : public FieldClosure {
178 CDSHeapVerifier* _verifier;
179 InstanceKlass* _ik; // The class whose static fields are being checked.
180 const char** _exclusions;
181 public:
269 }
270
271 if (ArchiveUtils::has_aot_initialized_mirror(ik)) {
272 // ik's <clinit> won't be executed at runtime, the static fields in
273 // ik will carry their values to runtime.
274 return;
275 }
276
277 CheckStaticFields csf(this, ik);
278 ik->do_local_static_fields(&csf);
279 }
280 }
281
282 void CDSHeapVerifier::add_static_obj_field(InstanceKlass* ik, oop field, Symbol* name) {
283 StaticFieldInfo info = {ik, name};
284 _table.put(field, info);
285 }
286
287 // This function is called once for every archived heap object. Warn if this object is referenced by
288 // a static field of a class that's not aot-initialized.
289 inline bool CDSHeapVerifier::do_entry(OopHandle& orig_obj_handle, HeapShared::CachedOopInfo& value) {
290 oop orig_obj = orig_obj_handle.resolve();
291 _archived_objs++;
292
293 if (java_lang_String::is_instance(orig_obj) && HeapShared::is_dumped_interned_string(orig_obj)) {
294 // It's quite often for static fields to have interned strings. These are most likely not
295 // problematic (and are hard to filter). So we will ignore them.
296 return true; /* keep on iterating */
297 }
298
299 StaticFieldInfo* info = _table.get(orig_obj);
300 if (info != nullptr) {
301 ResourceMark rm;
302 char* class_name = info->_holder->name()->as_C_string();
303 char* field_name = info->_name->as_C_string();
304 LogStream ls(Log(aot, heap)::warning());
305 ls.print_cr("Archive heap points to a static field that may hold a different value at runtime:");
306 ls.print_cr("Field: %s::%s", class_name, field_name);
307 ls.print("Value: ");
308 orig_obj->print_on(&ls);
309 ls.print_cr("--- trace begin ---");
310 trace_to_root(&ls, orig_obj, nullptr, &value);
320 oop _orig_obj;
321 oop _orig_field;
322 outputStream* _st;
323
324 public:
325 TraceFields(oop orig_obj, oop orig_field, outputStream* st)
326 : _orig_obj(orig_obj), _orig_field(orig_field), _st(st) {}
327
328 void do_field(fieldDescriptor* fd) {
329 if (fd->field_type() == T_OBJECT || fd->field_type() == T_ARRAY) {
330 oop obj_field = _orig_obj->obj_field(fd->offset());
331 if (obj_field == _orig_field) {
332 _st->print("::%s (offset = %d)", fd->name()->as_C_string(), fd->offset());
333 }
334 }
335 }
336 };
337
338 // Call this function (from gdb, etc) if you want to know why an object is archived.
339 void CDSHeapVerifier::trace_to_root(outputStream* st, oop orig_obj) {
340 HeapShared::CachedOopInfo* info = HeapShared::get_cached_oop_info(orig_obj);
341 if (info != nullptr) {
342 trace_to_root(st, orig_obj, nullptr, info);
343 } else {
344 st->print_cr("Not an archived object??");
345 }
346 }
347
348 const char* static_field_name(oop mirror, oop field) {
349 Klass* k = java_lang_Class::as_Klass(mirror);
350 if (k->is_instance_klass()) {
351 for (JavaFieldStream fs(InstanceKlass::cast(k)); !fs.done(); fs.next()) {
352 if (fs.access_flags().is_static()) {
353 fieldDescriptor& fd = fs.field_descriptor();
354 switch (fd.field_type()) {
355 case T_OBJECT:
356 case T_ARRAY:
357 if (mirror->obj_field(fd.offset()) == field) {
358 return fs.name()->as_C_string();
359 }
360 break;
361 default:
362 break;
363 }
364 }
365 }
366 }
367
368 return "<unknown>";
369 }
370
371 int CDSHeapVerifier::trace_to_root(outputStream* st, oop orig_obj, oop orig_field, HeapShared::CachedOopInfo* info) {
372 int level = 0;
373 if (info->orig_referrer() != nullptr) {
374 HeapShared::CachedOopInfo* ref = HeapShared::get_cached_oop_info(info->orig_referrer());
375 assert(ref != nullptr, "sanity");
376 level = trace_to_root(st, info->orig_referrer(), orig_obj, ref) + 1;
377 } else if (java_lang_String::is_instance(orig_obj)) {
378 st->print_cr("[%2d] (shared string table)", level++);
379 }
380 Klass* k = orig_obj->klass();
381 ResourceMark rm;
382 st->print("[%2d] ", level);
383 orig_obj->print_address_on(st);
384 st->print(" %s", k->internal_name());
385 if (java_lang_Class::is_instance(orig_obj)) {
386 st->print(" (%s::%s)", java_lang_Class::as_Klass(orig_obj)->external_name(), static_field_name(orig_obj, orig_field));
387 }
388 if (orig_field != nullptr) {
389 if (k->is_instance_klass()) {
390 TraceFields clo(orig_obj, orig_field, st);
391 InstanceKlass::cast(k)->do_nonstatic_fields(&clo);
392 } else {
393 assert(orig_obj->is_objArray(), "must be");
394 objArrayOop array = (objArrayOop)orig_obj;
|