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/compressedOops.inline.hpp"
 34 #include "oops/oop.inline.hpp"
 35 #include "oops/verifyOopClosure.hpp"
 36 #include "runtime/handles.inline.hpp"
 37 #include "runtime/javaThread.hpp"
 38 #include "runtime/synchronizer.hpp"
 39 #include "utilities/macros.hpp"
 40 
 41 void oopDesc::print_on(outputStream* st) const {
 42   if (*((juint*)this) == badHeapWordVal) {
 43     st->print("BAD WORD");
 44   } else if (*((juint*)this) == badMetaWordVal) {
 45     st->print("BAD META WORD");
 46   } else {
 47     klass()->oop_print_on(cast_to_oop(this), st);
 48   }
 49 }
 50 
 51 void oopDesc::print_address_on(outputStream* st) const {
 52   st->print("{" PTR_FORMAT "}", p2i(this));
 53 
 54 }
 55 
 56 void oopDesc::print()         { print_on(tty);         }
 57 
 58 void oopDesc::print_address() { print_address_on(tty); }
 59 
 60 char* oopDesc::print_string() {
 61   stringStream st;
 62   print_on(&st);
 63   return st.as_string();
 64 }
 65 
 66 void oopDesc::print_value() {
 67   print_value_on(tty);
 68 }
 69 
 70 char* oopDesc::print_value_string() {
 71   char buf[100];
 72   stringStream st(buf, sizeof(buf));
 73   print_value_on(&st);
 74   return st.as_string();
 75 }
 76 
 77 void oopDesc::print_value_on(outputStream* st) const {
 78   oop obj = const_cast<oopDesc*>(this);
 79   if (java_lang_String::is_instance(obj)) {
 80     java_lang_String::print(obj, st);
 81     print_address_on(st);
 82   } else {
 83     klass()->oop_print_value_on(obj, st);
 84   }
 85 }
 86 
 87 
 88 void oopDesc::verify_on(outputStream* st, oopDesc* oop_desc) {
 89   if (oop_desc != NULL) {
 90     oop_desc->klass()->oop_verify_on(oop_desc, st);
 91   }
 92 }
 93 
 94 
 95 void oopDesc::verify(oopDesc* oop_desc) {
 96   verify_on(tty, oop_desc);
 97 }
 98 
 99 intptr_t oopDesc::slow_identity_hash() {
100   // slow case; we have to acquire the micro lock in order to locate the header
101   Thread* current = Thread::current();
102   return ObjectSynchronizer::FastHashCode(current, this);
103 }
104 
105 // used only for asserts and guarantees
106 bool oopDesc::is_oop(oop obj, bool ignore_mark_word) {
107   if (!Universe::heap()->is_oop(obj)) {
108     return false;
109   }
110 
111   // Header verification: the mark is typically non-zero. If we're
112   // at a safepoint, it must not be zero.
113   // Outside of a safepoint, the header could be changing (for example,
114   // another thread could be inflating a lock on this object).
115   if (ignore_mark_word) {
116     return true;
117   }
118   if (obj->mark().value() != 0) {
119     return true;
120   }
121   return !SafepointSynchronize::is_at_safepoint() ;
122 }
123 
124 // used only for asserts and guarantees
125 bool oopDesc::is_oop_or_null(oop obj, bool ignore_mark_word) {
126   return obj == NULL ? true : is_oop(obj, ignore_mark_word);
127 }
128 
129 VerifyOopClosure VerifyOopClosure::verify_oop;
130 
131 template <class T> void VerifyOopClosure::do_oop_work(T* p) {
132   oop obj = RawAccess<>::oop_load(p);
133   guarantee(oopDesc::is_oop_or_null(obj), "invalid oop: " PTR_FORMAT, p2i(obj));
134 }
135 
136 void VerifyOopClosure::do_oop(oop* p)       { VerifyOopClosure::do_oop_work(p); }
137 void VerifyOopClosure::do_oop(narrowOop* p) { VerifyOopClosure::do_oop_work(p); }
138 
139 // type test operations that doesn't require inclusion of oop.inline.hpp.
140 bool oopDesc::is_instance_noinline()        const { return is_instance();         }
141 bool oopDesc::is_instanceRef_noinline()     const { return is_instanceRef();      }
142 bool oopDesc::is_stackChunk_noinline()      const { return is_stackChunk();       }
143 bool oopDesc::is_array_noinline()           const { return is_array();            }
144 bool oopDesc::is_objArray_noinline()        const { return is_objArray();         }
145 bool oopDesc::is_typeArray_noinline()       const { return is_typeArray();        }
146 bool oopDesc::is_flatArray_noinline()       const { return is_flatArray();        }
147 bool oopDesc::is_null_free_array_noinline() const { return is_null_free_array();  }
148 
149 bool oopDesc::has_klass_gap() {
150   // Only has a klass gap when compressed class pointers are used.
151   return UseCompressedClassPointers;
152 }
153 
154 #if INCLUDE_CDS_JAVA_HEAP
155 void oopDesc::set_narrow_klass(narrowKlass nk) {
156   assert(DumpSharedSpaces, "Used by CDS only. Do not abuse!");
157   assert(UseCompressedClassPointers, "must be");
158   _metadata._compressed_klass = nk;
159 }
160 #endif
161 
162 void* oopDesc::load_klass_raw(oop obj) {
163   if (UseCompressedClassPointers) {
164     narrowKlass narrow_klass = obj->_metadata._compressed_klass;
165     if (narrow_klass == 0) return NULL;
166     return (void*)CompressedKlassPointers::decode_raw(narrow_klass);
167   } else {
168     return obj->_metadata._klass;
169   }
170 }
171 
172 void* oopDesc::load_oop_raw(oop obj, int offset) {
173   uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
174   if (UseCompressedOops) {
175     narrowOop narrow_oop = *(narrowOop*)addr;
176     if (CompressedOops::is_null(narrow_oop)) return NULL;
177     return (void*)CompressedOops::decode_raw(narrow_oop);
178   } else {
179     return *(void**)addr;
180   }
181 }
182 
183 oop oopDesc::obj_field_acquire(int offset) const                      { return HeapAccess<MO_ACQUIRE>::oop_load_at(as_oop(), offset); }
184 
185 void oopDesc::obj_field_put_raw(int offset, oop value)                { RawAccess<>::oop_store_at(as_oop(), offset, value); }
186 void oopDesc::release_obj_field_put(int offset, oop value)            { HeapAccess<MO_RELEASE>::oop_store_at(as_oop(), offset, value); }
187 void oopDesc::obj_field_put_volatile(int offset, oop value)           { HeapAccess<MO_SEQ_CST>::oop_store_at(as_oop(), offset, value); }
188 
189 address oopDesc::address_field(int offset) const                      { return *field_addr<address>(offset); }
190 address oopDesc::address_field_acquire(int offset) const              { return Atomic::load_acquire(field_addr<address>(offset)); }
191 
192 void oopDesc::address_field_put(int offset, address value)            { *field_addr<address>(offset) = value; }
193 void oopDesc::release_address_field_put(int offset, address value)    { Atomic::release_store(field_addr<address>(offset), value); }
194 
195 Metadata* oopDesc::metadata_field(int offset) const                   { return *field_addr<Metadata*>(offset); }
196 void oopDesc::metadata_field_put(int offset, Metadata* value)         { *field_addr<Metadata*>(offset) = value; }
197 
198 Metadata* oopDesc::metadata_field_acquire(int offset) const           { return Atomic::load_acquire(field_addr<Metadata*>(offset)); }
199 void oopDesc::release_metadata_field_put(int offset, Metadata* value) { Atomic::release_store(field_addr<Metadata*>(offset), value); }
200 
201 jbyte oopDesc::byte_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jbyte>(offset)); }
202 void oopDesc::release_byte_field_put(int offset, jbyte value)         { Atomic::release_store(field_addr<jbyte>(offset), value); }
203 
204 jchar oopDesc::char_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jchar>(offset)); }
205 void oopDesc::release_char_field_put(int offset, jchar value)         { Atomic::release_store(field_addr<jchar>(offset), value); }
206 
207 jboolean oopDesc::bool_field_acquire(int offset) const                { return Atomic::load_acquire(field_addr<jboolean>(offset)); }
208 void oopDesc::release_bool_field_put(int offset, jboolean value)      { Atomic::release_store(field_addr<jboolean>(offset), jboolean(value & 1)); }
209 
210 jint oopDesc::int_field_acquire(int offset) const                     { return Atomic::load_acquire(field_addr<jint>(offset)); }
211 void oopDesc::release_int_field_put(int offset, jint value)           { Atomic::release_store(field_addr<jint>(offset), value); }
212 
213 jshort oopDesc::short_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jshort>(offset)); }
214 void oopDesc::release_short_field_put(int offset, jshort value)       { Atomic::release_store(field_addr<jshort>(offset), value); }
215 
216 jlong oopDesc::long_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jlong>(offset)); }
217 void oopDesc::release_long_field_put(int offset, jlong value)         { Atomic::release_store(field_addr<jlong>(offset), value); }
218 
219 jfloat oopDesc::float_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jfloat>(offset)); }
220 void oopDesc::release_float_field_put(int offset, jfloat value)       { Atomic::release_store(field_addr<jfloat>(offset), value); }
221 
222 jdouble oopDesc::double_field_acquire(int offset) const               { return Atomic::load_acquire(field_addr<jdouble>(offset)); }
223 void oopDesc::release_double_field_put(int offset, jdouble value)     { Atomic::release_store(field_addr<jdouble>(offset), value); }
224 
225 #ifdef ASSERT
226 void oopDesc::verify_forwardee(oop forwardee) {
227 #if INCLUDE_CDS_JAVA_HEAP
228   assert(!Universe::heap()->is_archived_object(forwardee) && !Universe::heap()->is_archived_object(this),
229          "forwarding archive object");
230 #endif
231 }
232 
233 bool oopDesc::size_might_change() {
234   // UseParallelGC and UseG1GC can change the length field
235   // of an "old copy" of an object array in the young gen so it indicates
236   // the grey portion of an already copied array. This will cause the first
237   // disjunct below to fail if the two comparands are computed across such
238   // a concurrent change.
239   return Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC);
240 }
241 #endif