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src/hotspot/share/cds/cppVtables.cpp

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 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/archiveUtils.hpp"
 27 #include "cds/archiveBuilder.hpp"
 28 #include "cds/cdsConfig.hpp"
 29 #include "cds/cppVtables.hpp"
 30 #include "cds/metaspaceShared.hpp"
 31 #include "logging/log.hpp"


 32 #include "oops/instanceClassLoaderKlass.hpp"

 33 #include "oops/instanceMirrorKlass.hpp"
 34 #include "oops/instanceRefKlass.hpp"
 35 #include "oops/instanceStackChunkKlass.hpp"
 36 #include "oops/methodData.hpp"
 37 #include "oops/objArrayKlass.hpp"
 38 #include "oops/typeArrayKlass.hpp"
 39 #include "runtime/arguments.hpp"
 40 #include "utilities/globalDefinitions.hpp"
 41 
 42 // Objects of the Metadata types (such as Klass and ConstantPool) have C++ vtables.
 43 // (In GCC this is the field <Type>::_vptr, i.e., first word in the object.)
 44 //
 45 // Addresses of the vtables and the methods may be different across JVM runs,
 46 // if libjvm.so is dynamically loaded at a different base address.
 47 //
 48 // To ensure that the Metadata objects in the CDS archive always have the correct vtable:
 49 //
 50 // + at dump time:  we redirect the _vptr to point to our own vtables inside
 51 //                  the CDS image
 52 // + at run time:   we clone the actual contents of the vtables from libjvm.so
 53 //                  into our own tables.
 54 
 55 // Currently, the archive contains ONLY the following types of objects that have C++ vtables.

 56 #define CPP_VTABLE_TYPES_DO(f) \
 57   f(ConstantPool) \
 58   f(InstanceKlass) \
 59   f(InstanceClassLoaderKlass) \
 60   f(InstanceMirrorKlass) \
 61   f(InstanceRefKlass) \
 62   f(InstanceStackChunkKlass) \
 63   f(Method) \
 64   f(ObjArrayKlass) \
 65   f(TypeArrayKlass)


 66 
 67 class CppVtableInfo {
 68   intptr_t _vtable_size;
 69   intptr_t _cloned_vtable[1]; // Pseudo flexible array member.
 70   static size_t cloned_vtable_offset() { return offset_of(CppVtableInfo, _cloned_vtable); }
 71 public:
 72   int vtable_size()           { return int(uintx(_vtable_size)); }
 73   void set_vtable_size(int n) { _vtable_size = intptr_t(n); }
 74   // Using _cloned_vtable[i] for i > 0 causes undefined behavior. We use address calculation instead.
 75   intptr_t* cloned_vtable()   { return (intptr_t*)((char*)this + cloned_vtable_offset()); }
 76   void zero()                 { memset(cloned_vtable(), 0, sizeof(intptr_t) * vtable_size()); }
 77   // Returns the address of the next CppVtableInfo that can be placed immediately after this CppVtableInfo
 78   static size_t byte_size(int vtable_size) {
 79     return cloned_vtable_offset() + (sizeof(intptr_t) * vtable_size);
 80   }
 81 };
 82 
 83 static inline intptr_t* vtable_of(const Metadata* m) {
 84   return *((intptr_t**)m);
 85 }

 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/archiveUtils.hpp"
 27 #include "cds/archiveBuilder.hpp"
 28 #include "cds/cdsConfig.hpp"
 29 #include "cds/cppVtables.hpp"
 30 #include "cds/metaspaceShared.hpp"
 31 #include "logging/log.hpp"
 32 #include "oops/flatArrayKlass.hpp"
 33 #include "oops/inlineKlass.hpp"
 34 #include "oops/instanceClassLoaderKlass.hpp"
 35 #include "oops/instanceKlass.inline.hpp"
 36 #include "oops/instanceMirrorKlass.hpp"
 37 #include "oops/instanceRefKlass.hpp"
 38 #include "oops/instanceStackChunkKlass.hpp"
 39 #include "oops/methodData.hpp"
 40 #include "oops/objArrayKlass.hpp"
 41 #include "oops/typeArrayKlass.hpp"
 42 #include "runtime/arguments.hpp"
 43 #include "utilities/globalDefinitions.hpp"
 44 
 45 // Objects of the Metadata types (such as Klass and ConstantPool) have C++ vtables.
 46 // (In GCC this is the field <Type>::_vptr, i.e., first word in the object.)
 47 //
 48 // Addresses of the vtables and the methods may be different across JVM runs,
 49 // if libjvm.so is dynamically loaded at a different base address.
 50 //
 51 // To ensure that the Metadata objects in the CDS archive always have the correct vtable:
 52 //
 53 // + at dump time:  we redirect the _vptr to point to our own vtables inside
 54 //                  the CDS image
 55 // + at run time:   we clone the actual contents of the vtables from libjvm.so
 56 //                  into our own tables.
 57 
 58 // Currently, the archive contains ONLY the following types of objects that have C++ vtables.
 59 // NOTE: this table must be in-sync with sun.jvm.hotspot.memory.FileMapInfo::populateMetadataTypeArray().
 60 #define CPP_VTABLE_TYPES_DO(f) \
 61   f(ConstantPool) \
 62   f(InstanceKlass) \
 63   f(InstanceClassLoaderKlass) \
 64   f(InstanceMirrorKlass) \
 65   f(InstanceRefKlass) \
 66   f(InstanceStackChunkKlass) \
 67   f(Method) \
 68   f(ObjArrayKlass) \
 69   f(TypeArrayKlass) \
 70   f(FlatArrayKlass) \
 71   f(InlineKlass)
 72 
 73 class CppVtableInfo {
 74   intptr_t _vtable_size;
 75   intptr_t _cloned_vtable[1]; // Pseudo flexible array member.
 76   static size_t cloned_vtable_offset() { return offset_of(CppVtableInfo, _cloned_vtable); }
 77 public:
 78   int vtable_size()           { return int(uintx(_vtable_size)); }
 79   void set_vtable_size(int n) { _vtable_size = intptr_t(n); }
 80   // Using _cloned_vtable[i] for i > 0 causes undefined behavior. We use address calculation instead.
 81   intptr_t* cloned_vtable()   { return (intptr_t*)((char*)this + cloned_vtable_offset()); }
 82   void zero()                 { memset(cloned_vtable(), 0, sizeof(intptr_t) * vtable_size()); }
 83   // Returns the address of the next CppVtableInfo that can be placed immediately after this CppVtableInfo
 84   static size_t byte_size(int vtable_size) {
 85     return cloned_vtable_offset() + (sizeof(intptr_t) * vtable_size);
 86   }
 87 };
 88 
 89 static inline intptr_t* vtable_of(const Metadata* m) {
 90   return *((intptr_t**)m);
 91 }
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