1 /*
   2  * Copyright (c) 1999, 2012, 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/ciKlass.hpp"
  27 #include "ci/ciSymbol.hpp"
  28 #include "ci/ciUtilities.hpp"
  29 #include "oops/oop.inline.hpp"
  30 
  31 // ciKlass
  32 //
  33 // This class represents a Klass* in the HotSpot virtual
  34 // machine.
  35 
  36 // ------------------------------------------------------------------
  37 // ciKlass::ciKlass
  38 ciKlass::ciKlass(KlassHandle h_k) : ciType(h_k) {
  39   assert(get_Klass()->is_klass(), "wrong type");
  40   Klass* k = get_Klass();
  41   _layout_helper = k->layout_helper();
  42   Symbol* klass_name = k->name();
  43   assert(klass_name != NULL, "wrong ciKlass constructor");
  44   _name = CURRENT_ENV->get_symbol(klass_name);
  45 }
  46 
  47 // ------------------------------------------------------------------
  48 // ciKlass::ciKlass
  49 //
  50 // Nameless klass variant.
  51 ciKlass::ciKlass(KlassHandle h_k, ciSymbol* name) : ciType(h_k) {
  52   assert(get_Klass()->is_klass(), "wrong type");
  53   _name = name;
  54   _layout_helper = Klass::_lh_neutral_value;
  55 }
  56 
  57 // ------------------------------------------------------------------
  58 // ciKlass::ciKlass
  59 //
  60 // Unloaded klass variant.
  61 ciKlass::ciKlass(ciSymbol* name, BasicType bt) : ciType(bt) {
  62   _name = name;
  63   _layout_helper = Klass::_lh_neutral_value;
  64 }
  65 
  66 // ------------------------------------------------------------------
  67 // ciKlass::is_subtype_of
  68 bool ciKlass::is_subtype_of(ciKlass* that) {
  69   assert(is_loaded() && that->is_loaded(), "must be loaded");
  70   // Check to see if the klasses are identical.
  71   if (this == that) {
  72     return true;
  73   }
  74 
  75   VM_ENTRY_MARK;
  76   Klass* this_klass = get_Klass();
  77   Klass* that_klass = that->get_Klass();
  78   bool result = this_klass->is_subtype_of(that_klass);
  79 
  80   return result;
  81 }
  82 
  83 // ------------------------------------------------------------------
  84 // ciKlass::is_subclass_of
  85 bool ciKlass::is_subclass_of(ciKlass* that) {
  86   assert(is_loaded() && that->is_loaded(), "must be loaded");
  87   // Check to see if the klasses are identical.
  88 
  89   VM_ENTRY_MARK;
  90   Klass* this_klass = get_Klass();
  91   Klass* that_klass = that->get_Klass();
  92   bool result = this_klass->is_subclass_of(that_klass);
  93 
  94   return result;
  95 }
  96 
  97 // ------------------------------------------------------------------
  98 // ciKlass::super_depth
  99 juint ciKlass::super_depth() {
 100   assert(is_loaded(), "must be loaded");
 101 
 102   VM_ENTRY_MARK;
 103   Klass* this_klass = get_Klass();
 104   return this_klass->super_depth();
 105 }
 106 
 107 // ------------------------------------------------------------------
 108 // ciKlass::super_check_offset
 109 juint ciKlass::super_check_offset() {
 110   assert(is_loaded(), "must be loaded");
 111 
 112   VM_ENTRY_MARK;
 113   Klass* this_klass = get_Klass();
 114   return this_klass->super_check_offset();
 115 }
 116 
 117 // ------------------------------------------------------------------
 118 // ciKlass::super_of_depth
 119 ciKlass* ciKlass::super_of_depth(juint i) {
 120   assert(is_loaded(), "must be loaded");
 121 
 122   VM_ENTRY_MARK;
 123   Klass* this_klass = get_Klass();
 124   Klass* super = this_klass->primary_super_of_depth(i);
 125   return (super != NULL) ? CURRENT_THREAD_ENV->get_klass(super) : NULL;
 126 }
 127 
 128 // ------------------------------------------------------------------
 129 // ciKlass::can_be_primary_super
 130 bool ciKlass::can_be_primary_super() {
 131   assert(is_loaded(), "must be loaded");
 132 
 133   VM_ENTRY_MARK;
 134   Klass* this_klass = get_Klass();
 135   return this_klass->can_be_primary_super();
 136 }
 137 
 138 // ------------------------------------------------------------------
 139 // ciKlass::least_common_ancestor
 140 //
 141 // Get the shared parent of two klasses.
 142 //
 143 // Implementation note: this method currently goes "over the wall"
 144 // and does all of the work on the VM side.  It could be rewritten
 145 // to use the super() method and do all of the work (aside from the
 146 // lazy computation of super()) in native mode.  This may be
 147 // worthwhile if the compiler is repeatedly requesting the same lca
 148 // computation or possibly if most of the superklasses have already
 149 // been created as ciObjects anyway.  Something to think about...
 150 ciKlass*
 151 ciKlass::least_common_ancestor(ciKlass* that) {
 152   assert(is_loaded() && that->is_loaded(), "must be loaded");
 153   // Check to see if the klasses are identical.
 154   if (this == that) {
 155     return this;
 156   }
 157 
 158   VM_ENTRY_MARK;
 159   Klass* this_klass = get_Klass();
 160   Klass* that_klass = that->get_Klass();
 161   Klass* lca        = this_klass->LCA(that_klass);
 162 
 163   // Many times the LCA will be either this_klass or that_klass.
 164   // Treat these as special cases.
 165   if (lca == that_klass) {
 166     return that;
 167   }
 168   if (this_klass == lca) {
 169     return this;
 170   }
 171 
 172   // Create the ciInstanceKlass for the lca.
 173   ciKlass* result =
 174     CURRENT_THREAD_ENV->get_klass(lca);
 175 
 176   return result;
 177 }
 178 
 179 // ------------------------------------------------------------------
 180 // ciKlass::find_klass
 181 //
 182 // Find a klass using this klass's class loader.
 183 ciKlass* ciKlass::find_klass(ciSymbol* klass_name) {
 184   assert(is_loaded(), "cannot find_klass through an unloaded klass");
 185   return CURRENT_ENV->get_klass_by_name(this,
 186                                         klass_name, false);
 187 }
 188 
 189 // ------------------------------------------------------------------
 190 // ciKlass::java_mirror
 191 //
 192 // Get the instance of java.lang.Class corresponding to this klass.
 193 // If it is an unloaded instance or array klass, return an unloaded
 194 // mirror object of type Class.
 195 ciInstance* ciKlass::java_mirror() {
 196   GUARDED_VM_ENTRY(
 197     if (!is_loaded())
 198       return ciEnv::current()->get_unloaded_klass_mirror(this);
 199     oop java_mirror = get_Klass()->java_mirror();
 200     return CURRENT_ENV->get_instance(java_mirror);
 201   )
 202 }
 203 
 204 // ------------------------------------------------------------------
 205 // ciKlass::modifier_flags
 206 jint ciKlass::modifier_flags() {
 207   assert(is_loaded(), "not loaded");
 208   GUARDED_VM_ENTRY(
 209     return get_Klass()->modifier_flags();
 210   )
 211 }
 212 
 213 // ------------------------------------------------------------------
 214 // ciKlass::access_flags
 215 jint ciKlass::access_flags() {
 216   assert(is_loaded(), "not loaded");
 217   GUARDED_VM_ENTRY(
 218     return get_Klass()->access_flags().as_int();
 219   )
 220 }
 221 
 222 // ------------------------------------------------------------------
 223 // ciKlass::print_impl
 224 //
 225 // Implementation of the print method
 226 void ciKlass::print_impl(outputStream* st) {
 227   st->print(" name=");
 228   print_name_on(st);
 229 }
 230 
 231 // ------------------------------------------------------------------
 232 // ciKlass::print_name
 233 //
 234 // Print the name of this klass
 235 void ciKlass::print_name_on(outputStream* st) {
 236   name()->print_symbol_on(st);
 237 }