1 /*
  2  * Copyright (c) 2018, 2021, 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 package sun.jvm.hotspot.memory;
 26 
 27 import java.util.*;
 28 import sun.jvm.hotspot.debugger.Address;
 29 import sun.jvm.hotspot.runtime.VM;
 30 import sun.jvm.hotspot.runtime.VMObject;
 31 import sun.jvm.hotspot.runtime.VMObjectFactory;
 32 import sun.jvm.hotspot.types.*;
 33 import sun.jvm.hotspot.utilities.Observable;
 34 import sun.jvm.hotspot.utilities.Observer;
 35 
 36 public class FileMapInfo {
 37   private static FileMapHeader headerObj;
 38 
 39   // Fields for handling the copied C++ vtables
 40   private static Address rwRegionBaseAddress;
 41   private static Address rwRegionEndAddress;
 42   private static Address vtablesIndex;
 43 
 44   // HashMap created by mapping the vTable addresses in the rw region with
 45   // the corresponding metadata type.
 46   private static Map<Address, Type> vTableTypeMap;
 47 
 48   private static Type metadataTypeArray[];
 49 
 50   static {
 51     VM.registerVMInitializedObserver(new Observer() {
 52         public void update(Observable o, Object data) {
 53           initialize(VM.getVM().getTypeDataBase());
 54         }
 55       });
 56   }
 57 
 58   static Address getStatic_AddressField(Type type, String fieldName) {
 59     AddressField field = type.getAddressField(fieldName);
 60     return field.getValue();
 61   }
 62 
 63   static Address get_AddressField(Type type, Address instance, String fieldName) {
 64     AddressField field = type.getAddressField(fieldName);
 65     return field.getValue(instance);
 66   }
 67 
 68   static long get_CIntegerField(Type type, Address instance, String fieldName) {
 69     CIntegerField field = type.getCIntegerField(fieldName);
 70     return field.getValue(instance);
 71   }
 72 
 73   // C equivalent:   return &header->_space[index];
 74   static Address get_CDSFileMapRegion(Type FileMapHeader_type, Address header, int index) {
 75     AddressField spaceField = FileMapHeader_type.getAddressField("_space[0]");
 76 
 77     // size_t offset = offsetof(FileMapHeader, _space[0]);
 78     // CDSFileMapRegion* space_0 = ((char*)header) + offset; // space_0 = &header->_space[index];
 79     // return ((char*)space_0) + index * sizeof(CDSFileMapRegion);
 80     long offset = spaceField.getOffset();
 81     Address space_0 = header.addOffsetTo(offset);
 82     return space_0.addOffsetTo(index * spaceField.getSize());
 83   }
 84 
 85   private static void initialize(TypeDataBase db) {
 86     Type FileMapInfo_type = db.lookupType("FileMapInfo");
 87     Type FileMapHeader_type = db.lookupType("FileMapHeader");
 88     Type CDSFileMapRegion_type = db.lookupType("CDSFileMapRegion");
 89 
 90     // FileMapInfo * info = FileMapInfo::_current_info;
 91     // FileMapHeader* header = info->_header
 92     Address info = getStatic_AddressField(FileMapInfo_type, "_current_info");
 93     Address header = get_AddressField(FileMapInfo_type, info, "_header");
 94     headerObj = (FileMapHeader) VMObjectFactory.newObject(FileMapInfo.FileMapHeader.class, header);
 95 
 96     // char* mapped_base_address = header->_mapped_base_address
 97     // size_t cloned_vtable_offset = header->_cloned_vtable_offset
 98     // CppVtableInfo** vtablesIndex = mapped_base_address + cloned_vtable_offset;
 99     Address mapped_base_address = get_AddressField(FileMapHeader_type, header, "_mapped_base_address");
100     long cloned_vtable_offset = get_CIntegerField(FileMapHeader_type, header, "_cloned_vtables_offset");
101     vtablesIndex = mapped_base_address.addOffsetTo(cloned_vtable_offset);
102 
103     // CDSFileMapRegion* rw_space = &header->_space[rw];
104     // char* rwRegionBaseAddress = rw_space->_mapped_base;
105     // size_t used = rw_space->_used;
106     // char* rwRegionEndAddress = rwRegionBaseAddress + used;
107     Address rw_space = get_CDSFileMapRegion(FileMapHeader_type, header, 0);
108     rwRegionBaseAddress = get_AddressField(CDSFileMapRegion_type, rw_space, "_mapped_base");
109     long used = get_CIntegerField(CDSFileMapRegion_type, rw_space, "_used");
110     rwRegionEndAddress = rwRegionBaseAddress.addOffsetTo(used);
111 
112     populateMetadataTypeArray(db);
113   }
114 
115   private static void populateMetadataTypeArray(TypeDataBase db) {
116     metadataTypeArray = new Type[8];
117 
118     metadataTypeArray[0] = db.lookupType("ConstantPool");
119     metadataTypeArray[1] = db.lookupType("InstanceKlass");
120     metadataTypeArray[2] = db.lookupType("InstanceClassLoaderKlass");
121     metadataTypeArray[3] = db.lookupType("InstanceMirrorKlass");
122     metadataTypeArray[4] = db.lookupType("InstanceRefKlass");
123     metadataTypeArray[5] = db.lookupType("Method");
124     metadataTypeArray[6] = db.lookupType("ObjArrayKlass");
125     metadataTypeArray[7] = db.lookupType("TypeArrayKlass");
126   }
127 
128   public FileMapHeader getHeader() {
129     return headerObj;
130   }
131 
132   public boolean inCopiedVtableSpace(Address vptrAddress) {
133     FileMapHeader fmHeader = getHeader();
134     return fmHeader.inCopiedVtableSpace(vptrAddress);
135   }
136 
137   public Type getTypeForVptrAddress(Address vptrAddress) {
138     if (vTableTypeMap == null) {
139       getHeader().createVtableTypeMapping();
140     }
141     return vTableTypeMap.get(vptrAddress);
142   }
143 
144 
145   //------------------------------------------------------------------------------------------
146 
147   public static class FileMapHeader extends VMObject {
148 
149     public FileMapHeader(Address addr) {
150       super(addr);
151     }
152 
153     public boolean inCopiedVtableSpace(Address vptrAddress) {
154       if (vptrAddress == null) {
155         return false;
156       }
157       if (vptrAddress.greaterThan(rwRegionBaseAddress) &&
158           vptrAddress.lessThanOrEqual(rwRegionEndAddress)) {
159         return true;
160       }
161       return false;
162     }
163 
164     public void createVtableTypeMapping() {
165       vTableTypeMap = new HashMap<Address, Type>();
166       long addressSize = VM.getVM().getAddressSize();
167 
168       // vtablesIndex points to this:
169       //     class CppVtableInfo {
170       //         intptr_t _vtable_size;
171       //         intptr_t _cloned_vtable[1];
172       //         ...
173       //     };
174       //     CppVtableInfo** CppVtables::_index;
175       // This is the index of all the cloned vtables. E.g., for
176       //     ConstantPool* cp = ....; // an archived constant pool
177       //     InstanceKlass* ik = ....;// an archived class
178       // the following holds true:
179       //     &_index[ConstantPool_Kind]->_cloned_vtable[0]  == ((intptr_t**)cp)[0]
180       //     &_index[InstanceKlass_Kind]->_cloned_vtable[0] == ((intptr_t**)ik)[0]
181 
182       for (int i=0; i < metadataTypeArray.length; i++) {
183         Address vtableInfoAddress = vtablesIndex.getAddressAt(i * addressSize); // = _index[i]
184         Address vtableAddress = vtableInfoAddress.addOffsetTo(addressSize); // = &_index[i]->_cloned_vtable[0]
185         vTableTypeMap.put(vtableAddress, metadataTypeArray[i]);
186       }
187     }
188   }
189 }