1 /*
  2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 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 "precompiled.hpp"
 26 #include "classfile/altHashing.hpp"
 27 #include "classfile/javaClasses.inline.hpp"
 28 #include "gc/shared/collectedHeap.inline.hpp"
 29 #include "gc/shared/gc_globals.hpp"
 30 #include "memory/resourceArea.hpp"
 31 #include "memory/universe.hpp"
 32 #include "oops/access.inline.hpp"
 33 #include "oops/compressedKlass.inline.hpp"
 34 #include "oops/compressedOops.inline.hpp"
 35 #include "oops/oop.inline.hpp"
 36 #include "oops/verifyOopClosure.hpp"
 37 #include "runtime/handles.inline.hpp"
 38 #include "runtime/interfaceSupport.inline.hpp"
 39 #include "runtime/javaThread.hpp"
 40 #include "utilities/macros.hpp"
 41 
 42 void oopDesc::print_on(outputStream* st) const {
 43   if (*((juint*)this) == badHeapWordVal) {
 44     st->print("BAD WORD");
 45   } else if (*((juint*)this) == badMetaWordVal) {
 46     st->print("BAD META WORD");
 47   } else {
 48     klass()->oop_print_on(cast_to_oop(this), st);
 49   }
 50 }
 51 
 52 void oopDesc::print_address_on(outputStream* st) const {
 53   st->print("{" INTPTR_FORMAT "}", p2i(this));
 54 
 55 }
 56 
 57 void oopDesc::print()         { print_on(tty);         }
 58 
 59 void oopDesc::print_address() { print_address_on(tty); }
 60 
 61 char* oopDesc::print_string() {
 62   stringStream st;
 63   print_on(&st);
 64   return st.as_string();
 65 }
 66 
 67 void oopDesc::print_value() {
 68   print_value_on(tty);
 69 }
 70 
 71 char* oopDesc::print_value_string() {
 72   char buf[100];
 73   stringStream st(buf, sizeof(buf));
 74   print_value_on(&st);
 75   return st.as_string();
 76 }
 77 
 78 void oopDesc::print_value_on(outputStream* st) const {
 79   oop obj = const_cast<oopDesc*>(this);
 80   if (java_lang_String::is_instance(obj)) {
 81     java_lang_String::print(obj, st);
 82     print_address_on(st);
 83   } else {
 84     klass()->oop_print_value_on(obj, st);
 85   }
 86 }
 87 
 88 
 89 void oopDesc::verify_on(outputStream* st, oopDesc* oop_desc) {
 90   if (oop_desc != NULL) {
 91     oop_desc->klass()->oop_verify_on(oop_desc, st);
 92   }
 93 }
 94 
 95 
 96 void oopDesc::verify(oopDesc* oop_desc) {
 97   verify_on(tty, oop_desc);
 98 }
 99 
100 intptr_t oopDesc::slow_identity_hash() {
101   // slow case; we have to acquire the micro lock in order to locate the header
102   Thread* current = Thread::current();
103   ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
104   HandleMark hm(current);
105   Handle object(current, this);
106   return ObjectSynchronizer::identity_hash_value_for(object);
107 }
108 
109 // used only for asserts and guarantees
110 bool oopDesc::is_oop(oop obj, bool ignore_mark_word) {
111   if (!Universe::heap()->is_oop(obj)) {
112     return false;
113   }
114 
115   // Header verification: the mark is typically non-zero. If we're
116   // at a safepoint, it must not be zero.
117   // Outside of a safepoint, the header could be changing (for example,
118   // another thread could be inflating a lock on this object).
119   if (ignore_mark_word) {
120     return true;
121   }
122   if (obj->mark().value() != 0) {
123     return true;
124   }
125   return !SafepointSynchronize::is_at_safepoint();
126 }
127 
128 // used only for asserts and guarantees
129 bool oopDesc::is_oop_or_null(oop obj, bool ignore_mark_word) {
130   return obj == NULL ? true : is_oop(obj, ignore_mark_word);
131 }
132 
133 VerifyOopClosure VerifyOopClosure::verify_oop;
134 
135 template <class T> void VerifyOopClosure::do_oop_work(T* p) {
136   oop obj = RawAccess<>::oop_load(p);
137   guarantee(oopDesc::is_oop_or_null(obj), "invalid oop: " INTPTR_FORMAT, p2i((oopDesc*) obj));
138 }
139 
140 void VerifyOopClosure::do_oop(oop* p)       { VerifyOopClosure::do_oop_work(p); }
141 void VerifyOopClosure::do_oop(narrowOop* p) { VerifyOopClosure::do_oop_work(p); }
142 
143 // type test operations that doesn't require inclusion of oop.inline.hpp.
144 bool oopDesc::is_instance_noinline()    const { return is_instance();    }
145 bool oopDesc::is_instanceRef_noinline() const { return is_instanceRef(); }
146 bool oopDesc::is_stackChunk_noinline()  const { return is_stackChunk();  }
147 bool oopDesc::is_array_noinline()       const { return is_array();       }
148 bool oopDesc::is_objArray_noinline()    const { return is_objArray();    }
149 bool oopDesc::is_typeArray_noinline()   const { return is_typeArray();   }
150 
151 void* oopDesc::load_klass_raw(oop obj) {
152   // TODO: Remove method altogether and replace with calls to obj->klass() ?
153   // OTOH, we may eventually get rid of locking in header, and then no
154   // longer have to deal with that anymore.
155 #ifdef _LP64
156   return obj->klass();
157 #else
158   return obj->_klass;
159 #endif
160 }
161 
162 void* oopDesc::load_oop_raw(oop obj, int offset) {
163   uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
164   if (UseCompressedOops) {
165     narrowOop narrow_oop = *(narrowOop*)addr;
166     if (CompressedOops::is_null(narrow_oop)) return NULL;
167     return (void*)CompressedOops::decode_raw(narrow_oop);
168   } else {
169     return *(void**)addr;
170   }
171 }
172 
173 #ifdef _LP64
174 JRT_LEAF(narrowKlass, oopDesc::load_nklass_runtime(oopDesc* o))
175   assert(o != NULL, "null-check");
176   oop obj = oop(o);
177   assert(oopDesc::is_oop(obj), "need a valid oop here: " PTR_FORMAT, p2i(o));
178   markWord header = obj->mark();
179   if (!header.is_neutral()) {
180     header = ObjectSynchronizer::stable_mark(obj);
181   }
182   assert(header.is_neutral(), "expect neutral header here");
183   narrowKlass nklass = header.narrow_klass();
184   return nklass;
185 JRT_END
186 #endif
187 
188 oop oopDesc::obj_field_acquire(int offset) const                      { return HeapAccess<MO_ACQUIRE>::oop_load_at(as_oop(), offset); }
189 
190 void oopDesc::obj_field_put_raw(int offset, oop value)                { RawAccess<>::oop_store_at(as_oop(), offset, value); }
191 void oopDesc::release_obj_field_put(int offset, oop value)            { HeapAccess<MO_RELEASE>::oop_store_at(as_oop(), offset, value); }
192 void oopDesc::obj_field_put_volatile(int offset, oop value)           { HeapAccess<MO_SEQ_CST>::oop_store_at(as_oop(), offset, value); }
193 
194 address oopDesc::address_field(int offset) const                      { return *field_addr<address>(offset); }
195 address oopDesc::address_field_acquire(int offset) const              { return Atomic::load_acquire(field_addr<address>(offset)); }
196 
197 void oopDesc::address_field_put(int offset, address value)            { *field_addr<address>(offset) = value; }
198 void oopDesc::release_address_field_put(int offset, address value)    { Atomic::release_store(field_addr<address>(offset), value); }
199 
200 Metadata* oopDesc::metadata_field(int offset) const                   { return *field_addr<Metadata*>(offset); }
201 void oopDesc::metadata_field_put(int offset, Metadata* value)         { *field_addr<Metadata*>(offset) = value; }
202 
203 Metadata* oopDesc::metadata_field_acquire(int offset) const           { return Atomic::load_acquire(field_addr<Metadata*>(offset)); }
204 void oopDesc::release_metadata_field_put(int offset, Metadata* value) { Atomic::release_store(field_addr<Metadata*>(offset), value); }
205 
206 jbyte oopDesc::byte_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jbyte>(offset)); }
207 void oopDesc::release_byte_field_put(int offset, jbyte value)         { Atomic::release_store(field_addr<jbyte>(offset), value); }
208 
209 jchar oopDesc::char_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jchar>(offset)); }
210 void oopDesc::release_char_field_put(int offset, jchar value)         { Atomic::release_store(field_addr<jchar>(offset), value); }
211 
212 jboolean oopDesc::bool_field_acquire(int offset) const                { return Atomic::load_acquire(field_addr<jboolean>(offset)); }
213 void oopDesc::release_bool_field_put(int offset, jboolean value)      { Atomic::release_store(field_addr<jboolean>(offset), jboolean(value & 1)); }
214 
215 jint oopDesc::int_field_acquire(int offset) const                     { return Atomic::load_acquire(field_addr<jint>(offset)); }
216 void oopDesc::release_int_field_put(int offset, jint value)           { Atomic::release_store(field_addr<jint>(offset), value); }
217 
218 jshort oopDesc::short_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jshort>(offset)); }
219 void oopDesc::release_short_field_put(int offset, jshort value)       { Atomic::release_store(field_addr<jshort>(offset), value); }
220 
221 jlong oopDesc::long_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jlong>(offset)); }
222 void oopDesc::release_long_field_put(int offset, jlong value)         { Atomic::release_store(field_addr<jlong>(offset), value); }
223 
224 jfloat oopDesc::float_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jfloat>(offset)); }
225 void oopDesc::release_float_field_put(int offset, jfloat value)       { Atomic::release_store(field_addr<jfloat>(offset), value); }
226 
227 jdouble oopDesc::double_field_acquire(int offset) const               { return Atomic::load_acquire(field_addr<jdouble>(offset)); }
228 void oopDesc::release_double_field_put(int offset, jdouble value)     { Atomic::release_store(field_addr<jdouble>(offset), value); }
229 
230 #ifdef ASSERT
231 void oopDesc::verify_forwardee(oop forwardee) {
232 #if INCLUDE_CDS_JAVA_HEAP
233   assert(!Universe::heap()->is_archived_object(forwardee) && !Universe::heap()->is_archived_object(this),
234          "forwarding archive object");
235 #endif
236 }
237 
238 bool oopDesc::size_might_change() {
239   // UseParallelGC and UseG1GC can change the length field
240   // of an "old copy" of an object array in the young gen so it indicates
241   // the grey portion of an already copied array. This will cause the first
242   // disjunct below to fail if the two comparands are computed across such
243   // a concurrent change.
244   return Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC);
245 }
246 #endif