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1 /* |
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2 * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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20 * CA 95054 USA or visit www.sun.com if you need additional information or |
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21 * have any questions. |
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22 * |
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23 */ |
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24 |
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25 // ciField |
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26 // |
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27 // This class represents the result of a field lookup in the VM. |
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28 // The lookup may not succeed, in which case the information in |
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29 // the ciField will be incomplete. |
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30 class ciField : public ResourceObj { |
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31 CI_PACKAGE_ACCESS |
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32 friend class ciEnv; |
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33 friend class ciInstanceKlass; |
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34 friend class NonStaticFieldFiller; |
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35 |
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36 private: |
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37 ciFlags _flags; |
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38 ciInstanceKlass* _holder; |
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39 ciSymbol* _name; |
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40 ciSymbol* _signature; |
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41 ciType* _type; |
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42 int _offset; |
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43 bool _is_constant; |
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44 ciInstanceKlass* _known_to_link_with; |
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45 ciConstant _constant_value; |
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46 |
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47 // Used for will_link |
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48 int _cp_index; |
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49 |
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50 ciType* compute_type(); |
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51 ciType* compute_type_impl(); |
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52 |
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53 ciField(ciInstanceKlass* klass, int index); |
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54 ciField(fieldDescriptor* fd); |
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55 |
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56 // shared constructor code |
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57 void initialize_from(fieldDescriptor* fd); |
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58 |
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59 // The implementation of the print method. |
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60 void print_impl(outputStream* st); |
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61 |
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62 public: |
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63 ciFlags flags() { return _flags; } |
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64 |
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65 // Of which klass is this field a member? |
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66 // |
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67 // Usage note: the declared holder of a field is the class |
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68 // referenced by name in the bytecodes. The canonical holder |
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69 // is the most general class which holds the field. This |
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70 // method returns the canonical holder. The declared holder |
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71 // can be accessed via a method in ciBytecodeStream. |
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72 // |
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73 // Ex. |
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74 // class A { |
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75 // public int f = 7; |
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76 // } |
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77 // class B extends A { |
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78 // public void test() { |
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79 // System.out.println(f); |
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80 // } |
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81 // } |
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82 // |
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83 // A java compiler is permitted to compile the access to |
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84 // field f as: |
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85 // |
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86 // getfield B.f |
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87 // |
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88 // In that case the declared holder of f would be B and |
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89 // the canonical holder of f would be A. |
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90 ciInstanceKlass* holder() { return _holder; } |
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91 |
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92 // Name of this field? |
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93 ciSymbol* name() { return _name; } |
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94 |
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95 // Signature of this field? |
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96 ciSymbol* signature() { return _signature; } |
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97 |
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98 // Of what type is this field? |
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99 ciType* type() { return (_type == NULL) ? compute_type() : _type; } |
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100 |
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101 // How is this field actually stored in memory? |
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102 BasicType layout_type() { return type2field[(_type == NULL) ? T_OBJECT : _type->basic_type()]; } |
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103 |
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104 // How big is this field in memory? |
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105 int size_in_bytes() { return type2aelembytes[layout_type()]; } |
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106 |
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107 // What is the offset of this field? |
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108 int offset() { |
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109 assert(_offset >= 1, "illegal call to offset()"); |
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110 return _offset; |
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111 } |
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112 |
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113 // Same question, explicit units. (Fields are aligned to the byte level.) |
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114 int offset_in_bytes() { |
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115 return offset(); |
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116 } |
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117 |
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118 // Is this field shared? |
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119 bool is_shared() { |
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120 // non-static fields of shared holders are cached |
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121 return _holder->is_shared() && !is_static(); |
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122 } |
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123 |
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124 // Is this field a constant? |
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125 // |
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126 // Clarification: A field is considered constant if: |
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127 // 1. The field is both static and final |
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128 // 2. The canonical holder of the field has undergone |
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129 // static initialization. |
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130 // 3. If the field is an object or array, then the oop |
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131 // in question is allocated in perm space. |
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132 // 4. The field is not one of the special static/final |
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133 // non-constant fields. These are java.lang.System.in |
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134 // and java.lang.System.out. Abomination. |
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135 // |
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136 // Note: the check for case 4 is not yet implemented. |
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137 bool is_constant() { return _is_constant; } |
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138 |
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139 // Get the constant value of this field. |
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140 ciConstant constant_value() { |
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141 assert(is_constant(), "illegal call to constant_value()"); |
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142 return _constant_value; |
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143 } |
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144 |
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145 // Check for link time errors. Accessing a field from a |
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146 // certain class via a certain bytecode may or may not be legal. |
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147 // This call checks to see if an exception may be raised by |
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148 // an access of this field. |
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149 // |
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150 // Usage note: if the same field is accessed multiple times |
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151 // in the same compilation, will_link will need to be checked |
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152 // at each point of access. |
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153 bool will_link(ciInstanceKlass* accessing_klass, |
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154 Bytecodes::Code bc); |
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155 |
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156 // Java access flags |
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157 bool is_public () { return flags().is_public(); } |
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158 bool is_private () { return flags().is_private(); } |
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159 bool is_protected () { return flags().is_protected(); } |
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160 bool is_static () { return flags().is_static(); } |
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161 bool is_final () { return flags().is_final(); } |
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162 bool is_volatile () { return flags().is_volatile(); } |
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163 bool is_transient () { return flags().is_transient(); } |
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164 |
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165 // Debugging output |
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166 void print(); |
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167 void print_name_on(outputStream* st); |
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168 }; |