1 /* 2 * Copyright (c) 1999, 2009, 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 "incls/_precompiled.incl" 26 #include "incls/_ciField.cpp.incl" 27 28 // ciField 29 // 30 // This class represents the result of a field lookup in the VM. 31 // The lookup may not succeed, in which case the information in 32 // the ciField will be incomplete. 33 34 // The ciObjectFactory cannot create circular data structures in one query. 35 // To avoid vicious circularities, we initialize ciField::_type to NULL 36 // for reference types and derive it lazily from the ciField::_signature. 37 // Primitive types are eagerly initialized, and basic layout queries 38 // can succeed without initialization, using only the BasicType of the field. 39 40 // Notes on bootstrapping and shared CI objects: A field is shared if and 41 // only if it is (a) non-static and (b) declared by a shared instance klass. 42 // This allows non-static field lists to be cached on shared types. 43 // Because the _type field is lazily initialized, however, there is a 44 // special restriction that a shared field cannot cache an unshared type. 45 // This puts a small performance penalty on shared fields with unshared 46 // types, such as StackTraceElement[] Throwable.stackTrace. | 1 /* 2 * Copyright (c) 1999, 2010, 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 "ci/ciField.hpp" 27 #include "ci/ciInstanceKlass.hpp" 28 #include "ci/ciUtilities.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "gc_interface/collectedHeap.inline.hpp" 31 #include "interpreter/linkResolver.hpp" 32 #include "memory/universe.inline.hpp" 33 #include "oops/oop.inline.hpp" 34 #include "oops/oop.inline2.hpp" 35 #include "runtime/fieldDescriptor.hpp" 36 37 // ciField 38 // 39 // This class represents the result of a field lookup in the VM. 40 // The lookup may not succeed, in which case the information in 41 // the ciField will be incomplete. 42 43 // The ciObjectFactory cannot create circular data structures in one query. 44 // To avoid vicious circularities, we initialize ciField::_type to NULL 45 // for reference types and derive it lazily from the ciField::_signature. 46 // Primitive types are eagerly initialized, and basic layout queries 47 // can succeed without initialization, using only the BasicType of the field. 48 49 // Notes on bootstrapping and shared CI objects: A field is shared if and 50 // only if it is (a) non-static and (b) declared by a shared instance klass. 51 // This allows non-static field lists to be cached on shared types. 52 // Because the _type field is lazily initialized, however, there is a 53 // special restriction that a shared field cannot cache an unshared type. 54 // This puts a small performance penalty on shared fields with unshared 55 // types, such as StackTraceElement[] Throwable.stackTrace. |