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.