1 /*
  2  * Copyright (c) 1999, 2021, 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 "classfile/javaClasses.inline.hpp"
 27 #include "ci/ciConstant.hpp"
 28 #include "ci/ciField.hpp"
 29 #include "ci/ciInstance.hpp"
 30 #include "ci/ciInstanceKlass.hpp"
 31 #include "ci/ciUtilities.inline.hpp"
 32 #include "classfile/vmClasses.hpp"
 33 #include "oops/oop.inline.hpp"
 34 
 35 // ciInstance
 36 //
 37 // This class represents an instanceOop in the HotSpot virtual
 38 // machine.
 39 
 40 // ------------------------------------------------------------------
 41 // ciObject::java_mirror_type
 42 ciType* ciInstance::java_mirror_type() {
 43   VM_ENTRY_MARK;
 44   oop m = get_oop();
 45   // Return NULL if it is not java.lang.Class.
 46   if (m == NULL || m->klass() != vmClasses::Class_klass()) {
 47     return NULL;
 48   }
 49   // Return either a primitive type or a klass.
 50   if (java_lang_Class::is_primitive(m)) {
 51     return ciType::make(java_lang_Class::primitive_type(m));
 52   } else {
 53     Klass* k = java_lang_Class::as_Klass(m);
 54     assert(k != NULL, "");
 55     return CURRENT_THREAD_ENV->get_klass(k);
 56   }
 57 }
 58 
 59 // ------------------------------------------------------------------
 60 // ciInstance::field_value_impl
 61 ciConstant ciInstance::field_value_impl(BasicType field_btype, int offset) {
 62   oop obj = get_oop();
 63   assert(obj != NULL, "bad oop");
 64   switch(field_btype) {
 65     case T_BYTE:    return ciConstant(field_btype, obj->byte_field(offset));
 66     case T_CHAR:    return ciConstant(field_btype, obj->char_field(offset));
 67     case T_SHORT:   return ciConstant(field_btype, obj->short_field(offset));
 68     case T_BOOLEAN: return ciConstant(field_btype, obj->bool_field(offset));
 69     case T_INT:     return ciConstant(field_btype, obj->int_field(offset));
 70     case T_FLOAT:   return ciConstant(obj->float_field(offset));
 71     case T_DOUBLE:  return ciConstant(obj->double_field(offset));
 72     case T_LONG:    return ciConstant(obj->long_field(offset));
 73     case T_OBJECT:  // fall through
 74     case T_ARRAY: {
 75       oop o = obj->obj_field(offset);
 76 
 77       // A field will be "constant" if it is known always to be
 78       // a non-null reference to an instance of a particular class,
 79       // or to a particular array.  This can happen even if the instance
 80       // or array is not perm.  In such a case, an "unloaded" ciArray
 81       // or ciInstance is created.  The compiler may be able to use
 82       // information about the object's class (which is exact) or length.
 83 
 84       if (o == NULL) {
 85         return ciConstant(field_btype, ciNullObject::make());
 86       } else {
 87         return ciConstant(field_btype, CURRENT_ENV->get_object(o));
 88       }
 89     }
 90     default:
 91       fatal("no field value: %s", type2name(field_btype));
 92       return ciConstant();
 93   }
 94 }
 95 
 96 // ------------------------------------------------------------------
 97 // ciInstance::field_value
 98 //
 99 // Constant value of a field.
100 ciConstant ciInstance::field_value(ciField* field) {
101   assert(is_loaded(), "invalid access - must be loaded");
102   assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
103   assert(field->is_static() || klass()->is_subclass_of(field->holder()), "invalid access - must be subclass");
104 
105   GUARDED_VM_ENTRY(return field_value_impl(field->type()->basic_type(), field->offset());)
106 }
107 
108 // ------------------------------------------------------------------
109 // ciInstance::field_value_by_offset
110 //
111 // Constant value of a field at the specified offset.
112 ciConstant ciInstance::field_value_by_offset(int field_offset) {
113   ciInstanceKlass* ik = klass()->as_instance_klass();
114   ciField* field = ik->get_field_by_offset(field_offset, false);
115   if (field == NULL)
116     return ciConstant();  // T_ILLEGAL
117   return field_value(field);
118 }
119 
120 // ------------------------------------------------------------------
121 // ciInstance::print_impl
122 //
123 // Implementation of the print method.
124 void ciInstance::print_impl(outputStream* st) {
125   st->print(" type=");
126   klass()->print(st);
127 }
128 
129 
130 ciKlass* ciInstance::java_lang_Class_klass() {
131   VM_ENTRY_MARK;
132   return CURRENT_ENV->get_metadata(java_lang_Class::as_Klass(get_oop()))->as_klass();
133 }