1 /*
   2  * Copyright (c) 1999, 2013, 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/ciConstant.hpp"
  27 #include "ci/ciField.hpp"
  28 #include "ci/ciInstance.hpp"
  29 #include "ci/ciInstanceKlass.hpp"
  30 #include "ci/ciUtilities.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "oops/oop.inline.hpp"
  33 
  34 // ciInstance
  35 //
  36 // This class represents an instanceOop in the HotSpot virtual
  37 // machine.
  38 
  39 // ------------------------------------------------------------------
  40 // ciObject::java_mirror_type
  41 ciType* ciInstance::java_mirror_type() {
  42   VM_ENTRY_MARK;
  43   oop m = get_oop();
  44   // Return NULL if it is not java.lang.Class.
  45   if (m == NULL || m->klass() != SystemDictionary::Class_klass()) {
  46     return NULL;
  47   }
  48   // Return either a primitive type or a klass.
  49   if (java_lang_Class::is_primitive(m)) {
  50     return ciType::make(java_lang_Class::primitive_type(m));
  51   } else {
  52     Klass* k = java_lang_Class::as_Klass(m);
  53     assert(k != NULL, "");
  54     return CURRENT_THREAD_ENV->get_klass(k);
  55   }
  56 }
  57 
  58 // ------------------------------------------------------------------
  59 // ciInstance::field_value
  60 //
  61 // Constant value of a field.
  62 ciConstant ciInstance::field_value(ciField* field) {
  63   assert(is_loaded(), "invalid access - must be loaded");
  64   assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
  65   assert(klass()->is_subclass_of(field->holder()), "invalid access - must be subclass");
  66 
  67   VM_ENTRY_MARK;
  68   Handle obj = get_oop();
  69   assert(!obj.is_null(), "bad oop");
  70   BasicType field_btype = field->type()->basic_type();
  71   int offset = field->offset();
  72 
  73   switch(field_btype) {
  74   case T_BYTE:
  75     return ciConstant(field_btype, obj->byte_field(offset));
  76     break;
  77   case T_CHAR:
  78     return ciConstant(field_btype, obj->char_field(offset));
  79     break;
  80   case T_SHORT:
  81     return ciConstant(field_btype, obj->short_field(offset));
  82     break;
  83   case T_BOOLEAN:
  84     return ciConstant(field_btype, obj->bool_field(offset));
  85     break;
  86   case T_INT:
  87     return ciConstant(field_btype, obj->int_field(offset));
  88     break;
  89   case T_FLOAT:
  90     return ciConstant(obj->float_field(offset));
  91     break;
  92   case T_DOUBLE:
  93     return ciConstant(obj->double_field(offset));
  94     break;
  95   case T_LONG:
  96     return ciConstant(obj->long_field(offset));
  97     break;
  98   case T_OBJECT:
  99   case T_ARRAY:
 100     {
 101       oop o = obj->obj_field(offset);
 102 
 103       // A field will be "constant" if it is known always to be
 104       // a non-null reference to an instance of a particular class,
 105       // or to a particular array.  This can happen even if the instance
 106       // or array is not perm.  In such a case, an "unloaded" ciArray
 107       // or ciInstance is created.  The compiler may be able to use
 108       // information about the object's class (which is exact) or length.
 109 
 110       if (o == NULL) {
 111         return ciConstant(field_btype, ciNullObject::make());
 112       } else {
 113         return ciConstant(field_btype, CURRENT_ENV->get_object(o));
 114       }
 115     }
 116   }
 117   ShouldNotReachHere();
 118   // to shut up the compiler
 119   return ciConstant();
 120 }
 121 
 122 // ------------------------------------------------------------------
 123 // ciInstance::field_value_by_offset
 124 //
 125 // Constant value of a field at the specified offset.
 126 ciConstant ciInstance::field_value_by_offset(int field_offset) {
 127   ciInstanceKlass* ik = klass()->as_instance_klass();
 128   ciField* field = ik->get_field_by_offset(field_offset, false);
 129   if (field == NULL)
 130     return ciConstant();  // T_ILLEGAL
 131   return field_value(field);
 132 }
 133 
 134 // ------------------------------------------------------------------
 135 // ciInstance::print_impl
 136 //
 137 // Implementation of the print method.
 138 void ciInstance::print_impl(outputStream* st) {
 139   st->print(" type=");
 140   klass()->print(st);
 141 }
 142 
 143 
 144 ciKlass* ciInstance::java_lang_Class_klass() {
 145   VM_ENTRY_MARK;
 146   return CURRENT_ENV->get_metadata(java_lang_Class::as_Klass(get_oop()))->as_klass();
 147 }