1 /*
   2  * Copyright (c) 1999, 2017, 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.inline.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_impl
  60 ciConstant ciInstance::field_value_impl(BasicType field_btype, int offset) {
  61   oop obj = get_oop();
  62   assert(obj != NULL, "bad oop");
  63   switch(field_btype) {
  64     case T_BYTE:    return ciConstant(field_btype, obj->byte_field(offset));
  65     case T_CHAR:    return ciConstant(field_btype, obj->char_field(offset));
  66     case T_SHORT:   return ciConstant(field_btype, obj->short_field(offset));
  67     case T_BOOLEAN: return ciConstant(field_btype, obj->bool_field(offset));
  68     case T_INT:     return ciConstant(field_btype, obj->int_field(offset));
  69     case T_FLOAT:   return ciConstant(obj->float_field(offset));
  70     case T_DOUBLE:  return ciConstant(obj->double_field(offset));
  71     case T_LONG:    return ciConstant(obj->long_field(offset));
  72     case T_OBJECT:  // fall through
  73     case T_ARRAY: {
  74       oop o = obj->obj_field(offset);
  75 
  76       // A field will be "constant" if it is known always to be
  77       // a non-null reference to an instance of a particular class,
  78       // or to a particular array.  This can happen even if the instance
  79       // or array is not perm.  In such a case, an "unloaded" ciArray
  80       // or ciInstance is created.  The compiler may be able to use
  81       // information about the object's class (which is exact) or length.
  82 
  83       if (o == NULL) {
  84         return ciConstant(field_btype, ciNullObject::make());
  85       } else {
  86         return ciConstant(field_btype, CURRENT_ENV->get_object(o));
  87       }
  88     }
  89     default:
  90       fatal("no field value: %s", type2name(field_btype));
  91       return ciConstant();
  92   }
  93 }
  94 
  95 // ------------------------------------------------------------------
  96 // ciInstance::field_value
  97 //
  98 // Constant value of a field.
  99 ciConstant ciInstance::field_value(ciField* field) {
 100   assert(is_loaded(), "invalid access - must be loaded");
 101   assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
 102   assert(field->is_static() || klass()->is_subclass_of(field->holder()), "invalid access - must be subclass");
 103 
 104   GUARDED_VM_ENTRY(return field_value_impl(field->type()->basic_type(), field->offset());)
 105 }
 106 
 107 // ------------------------------------------------------------------
 108 // ciInstance::field_value_by_offset
 109 //
 110 // Constant value of a field at the specified offset.
 111 ciConstant ciInstance::field_value_by_offset(int field_offset) {
 112   ciInstanceKlass* ik = klass()->as_instance_klass();
 113   ciField* field = ik->get_field_by_offset(field_offset, false);
 114   if (field == NULL)
 115     return ciConstant();  // T_ILLEGAL
 116   return field_value(field);
 117 }
 118 
 119 // ------------------------------------------------------------------
 120 // ciInstance::print_impl
 121 //
 122 // Implementation of the print method.
 123 void ciInstance::print_impl(outputStream* st) {
 124   st->print(" type=");
 125   klass()->print(st);
 126 }
 127 
 128 
 129 ciKlass* ciInstance::java_lang_Class_klass() {
 130   VM_ENTRY_MARK;
 131   return CURRENT_ENV->get_metadata(java_lang_Class::as_Klass(get_oop()))->as_klass();
 132 }