1 /*
  2  * Copyright (c) 1997, 2023, 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 "cds/cdsConfig.hpp"
 27 #include "classfile/altHashing.hpp"
 28 #include "classfile/javaClasses.inline.hpp"
 29 #include "gc/shared/collectedHeap.inline.hpp"
 30 #include "gc/shared/gc_globals.hpp"
 31 #include "memory/resourceArea.hpp"
 32 #include "memory/universe.hpp"
 33 #include "oops/access.inline.hpp"
 34 #include "oops/compressedKlass.inline.hpp"
 35 #include "oops/compressedOops.inline.hpp"
 36 #include "oops/oop.inline.hpp"
 37 #include "oops/verifyOopClosure.hpp"
 38 #include "runtime/handles.inline.hpp"
 39 #include "runtime/javaThread.hpp"
 40 #include "runtime/synchronizer.hpp"
 41 #include "utilities/macros.hpp"
 42 
 43 void oopDesc::print_on(outputStream* st) const {
 44   if (*((juint*)this) == badHeapWordVal) {
 45     st->print_cr("BAD 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_name_on(outputStream* st) const {
 57   if (*((juint*)this) == badHeapWordVal) {
 58     st->print_cr("BAD WORD");
 59   } else {
 60     st->print_cr("%s", klass()->external_name());
 61   }
 62 }
 63 
 64 void oopDesc::print()         { print_on(tty);         }
 65 
 66 void oopDesc::print_address() { print_address_on(tty); }
 67 
 68 char* oopDesc::print_string() {
 69   stringStream st;
 70   print_on(&st);
 71   return st.as_string();
 72 }
 73 
 74 void oopDesc::print_value() {
 75   print_value_on(tty);
 76 }
 77 
 78 char* oopDesc::print_value_string() {
 79   char buf[100];
 80   stringStream st(buf, sizeof(buf));
 81   print_value_on(&st);
 82   return st.as_string();
 83 }
 84 
 85 void oopDesc::print_value_on(outputStream* st) const {
 86   oop obj = const_cast<oopDesc*>(this);
 87   if (java_lang_String::is_instance(obj)) {
 88     java_lang_String::print(obj, st);
 89     print_address_on(st);
 90   } else {
 91     klass()->oop_print_value_on(obj, st);
 92   }
 93 }
 94 
 95 
 96 void oopDesc::verify_on(outputStream* st, oopDesc* oop_desc) {
 97   if (oop_desc != nullptr) {
 98     oop_desc->klass()->oop_verify_on(oop_desc, st);
 99   }
100 }
101 
102 
103 void oopDesc::verify(oopDesc* oop_desc) {
104   verify_on(tty, oop_desc);
105 }
106 
107 intptr_t oopDesc::slow_identity_hash() {
108   // slow case; we have to acquire the micro lock in order to locate the header
109   Thread* current = Thread::current();
110   return ObjectSynchronizer::FastHashCode(current, this);
111 }
112 
113 // used only for asserts and guarantees
114 bool oopDesc::is_oop(oop obj, bool ignore_mark_word) {
115   if (!Universe::heap()->is_oop(obj)) {
116     return false;
117   }
118 
119   // Header verification: the mark is typically non-zero. If we're
120   // at a safepoint, it must not be zero, except when using the new lightweight locking.
121   // Outside of a safepoint, the header could be changing (for example,
122   // another thread could be inflating a lock on this object).
123   if (ignore_mark_word) {
124     return true;
125   }
126   if (obj->mark().value() != 0) {
127     return true;
128   }
129   return LockingMode == LM_LIGHTWEIGHT || !SafepointSynchronize::is_at_safepoint();
130 }
131 
132 // used only for asserts and guarantees
133 bool oopDesc::is_oop_or_null(oop obj, bool ignore_mark_word) {
134   return obj == nullptr ? true : is_oop(obj, ignore_mark_word);
135 }
136 
137 VerifyOopClosure VerifyOopClosure::verify_oop;
138 
139 template <class T> void VerifyOopClosure::do_oop_work(T* p) {
140   oop obj = RawAccess<>::oop_load(p);
141   guarantee(oopDesc::is_oop_or_null(obj), "invalid oop: " PTR_FORMAT, p2i(obj));
142 }
143 
144 void VerifyOopClosure::do_oop(oop* p)       { VerifyOopClosure::do_oop_work(p); }
145 void VerifyOopClosure::do_oop(narrowOop* p) { VerifyOopClosure::do_oop_work(p); }
146 
147 // type test operations that doesn't require inclusion of oop.inline.hpp.
148 bool oopDesc::is_instance_noinline()    const { return is_instance();    }
149 bool oopDesc::is_instanceRef_noinline() const { return is_instanceRef(); }
150 bool oopDesc::is_stackChunk_noinline()  const { return is_stackChunk();  }
151 bool oopDesc::is_array_noinline()       const { return is_array();       }
152 bool oopDesc::is_objArray_noinline()    const { return is_objArray();    }
153 bool oopDesc::is_typeArray_noinline()   const { return is_typeArray();   }
154 
155 bool oopDesc::has_klass_gap() {
156   // Only has a klass gap when compressed class pointers are used.
157   return UseCompressedClassPointers;
158 }
159 
160 #if INCLUDE_CDS_JAVA_HEAP
161 void oopDesc::set_narrow_klass(narrowKlass nk) {
162   assert(CDSConfig::is_dumping_heap(), "Used by CDS only. Do not abuse!");
163   assert(UseCompressedClassPointers, "must be");
164   _metadata._compressed_klass = nk;
165 }
166 #endif
167 
168 void* oopDesc::load_oop_raw(oop obj, int offset) {
169   uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
170   if (UseCompressedOops) {
171     narrowOop narrow_oop = *(narrowOop*)addr;
172     if (CompressedOops::is_null(narrow_oop)) return nullptr;
173     return (void*)CompressedOops::decode_raw(narrow_oop);
174   } else {
175     return *(void**)addr;
176   }
177 }
178 
179 oop oopDesc::obj_field_acquire(int offset) const                      { return HeapAccess<MO_ACQUIRE>::oop_load_at(as_oop(), offset); }
180 
181 void oopDesc::obj_field_put_raw(int offset, oop value)                { assert(!(UseZGC && ZGenerational), "Generational ZGC must use store barriers");
182                                                                         RawAccess<>::oop_store_at(as_oop(), offset, value); }
183 void oopDesc::release_obj_field_put(int offset, oop value)            { HeapAccess<MO_RELEASE>::oop_store_at(as_oop(), offset, value); }
184 void oopDesc::obj_field_put_volatile(int offset, oop value)           { HeapAccess<MO_SEQ_CST>::oop_store_at(as_oop(), offset, value); }
185 
186 address oopDesc::address_field(int offset) const                      { return *field_addr<address>(offset); }
187 address oopDesc::address_field_acquire(int offset) const              { return Atomic::load_acquire(field_addr<address>(offset)); }
188 
189 void oopDesc::address_field_put(int offset, address value)            { *field_addr<address>(offset) = value; }
190 void oopDesc::release_address_field_put(int offset, address value)    { Atomic::release_store(field_addr<address>(offset), value); }
191 
192 Metadata* oopDesc::metadata_field(int offset) const                   { return *field_addr<Metadata*>(offset); }
193 void oopDesc::metadata_field_put(int offset, Metadata* value)         { *field_addr<Metadata*>(offset) = value; }
194 
195 Metadata* oopDesc::metadata_field_acquire(int offset) const           { return Atomic::load_acquire(field_addr<Metadata*>(offset)); }
196 void oopDesc::release_metadata_field_put(int offset, Metadata* value) { Atomic::release_store(field_addr<Metadata*>(offset), value); }
197 
198 jbyte oopDesc::byte_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jbyte>(offset)); }
199 void oopDesc::release_byte_field_put(int offset, jbyte value)         { Atomic::release_store(field_addr<jbyte>(offset), value); }
200 
201 jchar oopDesc::char_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jchar>(offset)); }
202 void oopDesc::release_char_field_put(int offset, jchar value)         { Atomic::release_store(field_addr<jchar>(offset), value); }
203 
204 jboolean oopDesc::bool_field_acquire(int offset) const                { return Atomic::load_acquire(field_addr<jboolean>(offset)); }
205 void oopDesc::release_bool_field_put(int offset, jboolean value)      { Atomic::release_store(field_addr<jboolean>(offset), jboolean(value & 1)); }
206 
207 jint oopDesc::int_field_acquire(int offset) const                     { return Atomic::load_acquire(field_addr<jint>(offset)); }
208 void oopDesc::release_int_field_put(int offset, jint value)           { Atomic::release_store(field_addr<jint>(offset), value); }
209 
210 jshort oopDesc::short_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jshort>(offset)); }
211 void oopDesc::release_short_field_put(int offset, jshort value)       { Atomic::release_store(field_addr<jshort>(offset), value); }
212 
213 jlong oopDesc::long_field_acquire(int offset) const                   { return Atomic::load_acquire(field_addr<jlong>(offset)); }
214 void oopDesc::release_long_field_put(int offset, jlong value)         { Atomic::release_store(field_addr<jlong>(offset), value); }
215 
216 jfloat oopDesc::float_field_acquire(int offset) const                 { return Atomic::load_acquire(field_addr<jfloat>(offset)); }
217 void oopDesc::release_float_field_put(int offset, jfloat value)       { Atomic::release_store(field_addr<jfloat>(offset), value); }
218 
219 jdouble oopDesc::double_field_acquire(int offset) const               { return Atomic::load_acquire(field_addr<jdouble>(offset)); }
220 void oopDesc::release_double_field_put(int offset, jdouble value)     { Atomic::release_store(field_addr<jdouble>(offset), value); }
221 
222 #ifdef ASSERT
223 bool oopDesc::size_might_change() {
224   // UseParallelGC and UseG1GC can change the length field
225   // of an "old copy" of an object array in the young gen so it indicates
226   // the grey portion of an already copied array. This will cause the first
227   // disjunct below to fail if the two comparands are computed across such
228   // a concurrent change.
229   return Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC);
230 }
231 #endif