1 /*
  2  * Copyright (c) 1999, 2023, 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/ciNullObject.hpp"
 32 #include "ci/ciUtilities.inline.hpp"
 33 #include "classfile/vmClasses.hpp"
 34 #include "oops/oop.inline.hpp"
 35 
 36 // ciInstance
 37 //
 38 // This class represents an instanceOop in the HotSpot virtual
 39 // machine.
 40 
 41 // ------------------------------------------------------------------
 42 // ciObject::java_mirror_type
 43 ciType* ciInstance::java_mirror_type(bool* is_null_free_array) {
 44   VM_ENTRY_MARK;
 45   oop m = get_oop();
 46   // Return null if it is not java.lang.Class.
 47   if (m == nullptr || m->klass() != vmClasses::Class_klass()) {
 48     return nullptr;
 49   }
 50   // Return either a primitive type or a klass.
 51   if (java_lang_Class::is_primitive(m)) {
 52     return ciType::make(java_lang_Class::primitive_type(m));
 53   } else {
 54     Klass* k = java_lang_Class::as_Klass(m);
 55     assert(k != nullptr, "");
 56     if (is_null_free_array != nullptr && (k->is_flatArray_klass() || (k->is_objArray_klass() && k->is_null_free_array_klass()))) {
 57       *is_null_free_array = true;
 58     }
 59     return CURRENT_THREAD_ENV->get_klass(k);
 60   }
 61 }
 62 
 63 // ------------------------------------------------------------------
 64 // ciInstance::field_value_impl
 65 ciConstant ciInstance::field_value_impl(BasicType field_btype, int offset) {
 66   ciConstant value = check_constant_value_cache(offset, field_btype);
 67   if (value.is_valid()) {
 68     return value;
 69   }
 70   VM_ENTRY_MARK;
 71   oop obj = get_oop();
 72   assert(obj != nullptr, "bad oop");
 73   switch(field_btype) {
 74     case T_BYTE:    value = ciConstant(field_btype, obj->byte_field(offset)); break;
 75     case T_CHAR:    value = ciConstant(field_btype, obj->char_field(offset)); break;
 76     case T_SHORT:   value = ciConstant(field_btype, obj->short_field(offset)); break;
 77     case T_BOOLEAN: value = ciConstant(field_btype, obj->bool_field(offset)); break;
 78     case T_INT:     value = ciConstant(field_btype, obj->int_field(offset)); break;
 79     case T_FLOAT:   value = ciConstant(obj->float_field(offset)); break;
 80     case T_DOUBLE:  value = ciConstant(obj->double_field(offset)); break;
 81     case T_LONG:    value = ciConstant(obj->long_field(offset)); break;
 82     case T_OBJECT:  // fall through
 83     case T_ARRAY: {
 84       oop o = obj->obj_field(offset);
 85 
 86       // A field will be "constant" if it is known always to be
 87       // a non-null reference to an instance of a particular class,
 88       // or to a particular array.  This can happen even if the instance
 89       // or array is not perm.  In such a case, an "unloaded" ciArray
 90       // or ciInstance is created.  The compiler may be able to use
 91       // information about the object's class (which is exact) or length.
 92 
 93       if (o == nullptr) {
 94         value = ciConstant(field_btype, ciNullObject::make());
 95       } else {
 96         value = ciConstant(field_btype, CURRENT_ENV->get_object(o));
 97       }
 98       break;
 99     }
100     default:
101       fatal("no field value: %s", type2name(field_btype));
102   }
103   add_to_constant_value_cache(offset, value);
104   return value;
105 }
106 
107 // ------------------------------------------------------------------
108 // ciInstance::field_value
109 //
110 // Constant value of a field.
111 ciConstant ciInstance::field_value(ciField* field) {
112   assert(is_loaded(), "invalid access - must be loaded");
113   assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
114   assert(field->is_static() || field->holder()->is_inlinetype() || klass()->is_subclass_of(field->holder()),
115          "invalid access - must be subclass");
116 
117   return field_value_impl(field->type()->basic_type(), field->offset_in_bytes());
118 }
119 
120 // ------------------------------------------------------------------
121 // ciInstance::field_value_by_offset
122 //
123 // Constant value of a field at the specified offset.
124 ciConstant ciInstance::field_value_by_offset(int field_offset) {
125   ciInstanceKlass* ik = klass()->as_instance_klass();
126   ciField* field = ik->get_field_by_offset(field_offset, false);
127   if (field == nullptr)
128     return ciConstant();  // T_ILLEGAL
129   return field_value(field);
130 }
131 
132 // ------------------------------------------------------------------
133 // ciInstance::print_impl
134 //
135 // Implementation of the print method.
136 void ciInstance::print_impl(outputStream* st) {
137   st->print(" type=");
138   klass()->print(st);
139 }
140 
141 
142 ciKlass* ciInstance::java_lang_Class_klass() {
143   VM_ENTRY_MARK;
144   assert(java_lang_Class::as_Klass(get_oop()) != nullptr, "klass is null");
145   return CURRENT_ENV->get_metadata(java_lang_Class::as_Klass(get_oop()))->as_klass();
146 }