1 /*
   2  * Copyright (c) 1997, 2018, 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 #ifndef SHARE_VM_RUNTIME_FIELDDESCRIPTOR_HPP
  26 #define SHARE_VM_RUNTIME_FIELDDESCRIPTOR_HPP
  27 
  28 #include "oops/constantPool.hpp"
  29 #include "oops/fieldInfo.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "oops/symbol.hpp"
  32 #include "runtime/fieldType.hpp"
  33 #include "utilities/accessFlags.hpp"
  34 #include "utilities/constantTag.hpp"
  35 
  36 // A fieldDescriptor describes the attributes of a single field (instance or class variable).
  37 // It needs the class constant pool to work (because it only holds indices into the pool
  38 // rather than the actual info).
  39 
  40 class fieldDescriptor {
  41  private:
  42   AccessFlags         _access_flags;
  43   int                 _index; // the field index
  44   constantPoolHandle  _cp;
  45 
  46   // update the access_flags for the field in the klass
  47   void update_klass_field_access_flag() {
  48     InstanceKlass* ik = field_holder();
  49     ik->field(index())->set_access_flags(_access_flags.as_short());
  50   }
  51 
  52   FieldInfo* field() const {
  53     InstanceKlass* ik = field_holder();
  54     return ik->field(_index);
  55   }
  56 
  57  public:
  58   fieldDescriptor() {
  59     DEBUG_ONLY(_index = badInt);
  60   }
  61   fieldDescriptor(InstanceKlass* ik, int index) {
  62     DEBUG_ONLY(_index = badInt);
  63     reinitialize(ik, index);
  64   }
  65   Symbol* name() const {
  66     return field()->name(_cp());
  67   }
  68   Symbol* signature() const {
  69     return field()->signature(_cp());
  70   }
  71   InstanceKlass* field_holder()   const    { return _cp->pool_holder(); }
  72   ConstantPool* constants()       const    { return _cp(); }
  73   AccessFlags access_flags()      const    { return _access_flags; }
  74   oop loader()                    const;
  75   // Offset (in words) of field from start of instanceOop / Klass*
  76   int offset()                    const    { return field()->offset(); }
  77   Symbol* generic_signature()     const;
  78   int index()                     const    { return _index; }
  79   AnnotationArray* annotations()  const;
  80   AnnotationArray* type_annotations()  const;
  81 
  82   // Initial field value
  83   bool has_initial_value()        const    { return field()->initval_index() != 0; }
  84   int initial_value_index()       const    { return field()->initval_index(); }
  85   constantTag initial_value_tag() const;  // The tag will return true on one of is_int(), is_long(), is_single(), is_double()
  86   jint int_initial_value()        const;
  87   jlong long_initial_value()      const;
  88   jfloat float_initial_value()    const;
  89   jdouble double_initial_value()  const;
  90   oop string_initial_value(TRAPS) const;
  91 
  92   // Field signature type
  93   BasicType field_type()          const    { return FieldType::basic_type(signature()); }
  94 
  95   // Access flags
  96   bool is_public()                const    { return access_flags().is_public(); }
  97   bool is_private()               const    { return access_flags().is_private(); }
  98   bool is_protected()             const    { return access_flags().is_protected(); }
  99   bool is_package_private()       const    { return !is_public() && !is_private() && !is_protected(); }
 100 
 101   bool is_static()                const    { return access_flags().is_static(); }
 102   bool is_final()                 const    { return access_flags().is_final(); }
 103   bool is_stable()                const    { return access_flags().is_stable(); }
 104   bool is_volatile()              const    { return access_flags().is_volatile(); }
 105   bool is_transient()             const    { return access_flags().is_transient(); }
 106 
 107   bool is_synthetic()             const    { return access_flags().is_synthetic(); }
 108 
 109   bool is_field_access_watched()  const    { return access_flags().is_field_access_watched(); }
 110   bool is_field_modification_watched() const
 111                                            { return access_flags().is_field_modification_watched(); }
 112   bool has_initialized_final_update() const { return access_flags().has_field_initialized_final_update(); }
 113   bool has_generic_signature()    const    { return access_flags().field_has_generic_signature(); }
 114 
 115   void set_is_field_access_watched(const bool value) {
 116     _access_flags.set_is_field_access_watched(value);
 117     update_klass_field_access_flag();
 118   }
 119 
 120   void set_is_field_modification_watched(const bool value) {
 121     _access_flags.set_is_field_modification_watched(value);
 122     update_klass_field_access_flag();
 123   }
 124 
 125   void set_has_initialized_final_update(const bool value) {
 126     _access_flags.set_has_field_initialized_final_update(value);
 127     update_klass_field_access_flag();
 128   }
 129 
 130   // Initialization
 131   void reinitialize(InstanceKlass* ik, int index);
 132 
 133   // Print
 134   void print() { print_on(tty); }
 135   void print_on(outputStream* st) const         PRODUCT_RETURN;
 136   void print_on_for(outputStream* st, oop obj)  PRODUCT_RETURN;
 137   void verify() const                           PRODUCT_RETURN;
 138 };
 139 
 140 #endif // SHARE_VM_RUNTIME_FIELDDESCRIPTOR_HPP