1 /*
  2  * Copyright (c) 1999, 2020, 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
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 24 
 25 #ifndef SHARE_CI_CIKLASS_HPP
 26 #define SHARE_CI_CIKLASS_HPP
 27 
 28 #include "ci/ciType.hpp"
 29 #include "oops/klass.hpp"
 30 
 31 // ciKlass
 32 //
 33 // This class and its subclasses represent Klass*s in the
 34 // HotSpot virtual machine.  In the vm, each Klass* contains an
 35 // embedded Klass object.  ciKlass is subclassed to explicitly
 36 // represent the kind of Klass embedded in the Klass*.  For
 37 // example, a Klass* with an embedded ObjArrayKlass object is
 38 // represented in the ciObject hierarchy by the class
 39 // ciObjArrayKlass.
 40 class ciKlass : public ciType {
 41   CI_PACKAGE_ACCESS
 42   friend class ciEnv;
 43   friend class ciField;
 44   friend class ciMethod;
 45   friend class ciMethodData;
 46   friend class ciObjArrayKlass;
 47   friend class ciReceiverTypeData;
 48   friend class ciSignature;
 49   friend class ciFlatArrayKlass;
 50   friend class ciArrayKlass;
 51 
 52 private:
 53   ciSymbol* _name;
 54   jint _layout_helper;
 55 
 56 protected:
 57   ciKlass(Klass* k, ciSymbol* name);
 58   ciKlass(ciSymbol* name, BasicType bt);
 59 
 60   Klass* get_Klass() const {
 61     Klass* k = (Klass*)_metadata;
 62     assert(k != NULL, "illegal use of unloaded klass");
 63     return k;
 64   }
 65 
 66   // Certain subklasses have an associated class loader.
 67   virtual oop loader()             { return NULL; }
 68   virtual jobject loader_handle()  { return NULL; }
 69 
 70   virtual oop protection_domain()             { return NULL; }
 71   virtual jobject protection_domain_handle()  { return NULL; }
 72 
 73   const char* type_string() { return "ciKlass"; }
 74 
 75   void print_impl(outputStream* st);
 76 
 77 public:
 78   ciKlass(Klass* k);
 79 
 80   // What is the name of this klass?
 81   ciSymbol* name() const { return _name; }
 82 
 83   // What is its layout helper value?
 84   jint layout_helper() { return _layout_helper; }
 85 
 86   bool is_subtype_of(ciKlass* klass);
 87   bool is_subclass_of(ciKlass* klass);
 88   juint super_depth();
 89   juint super_check_offset();
 90   ciKlass* super_of_depth(juint i);
 91   static juint primary_super_limit() { return Klass::primary_super_limit(); }
 92 
 93   // Is this ciObject the ciInstanceKlass representing java.lang.Object()?
 94   virtual bool is_java_lang_Object() const  { return false; }
 95 
 96   // Get the shared parent of two klasses.
 97   ciKlass* least_common_ancestor(ciKlass* k);
 98 
 99   virtual bool is_interface() {
100     return false;
101   }
102 
103   virtual bool is_abstract() {
104     return false;
105   }
106 
107   // Does this type (array, class, interface) have no subtypes?
108   virtual bool is_leaf_type() {
109     return false;
110   }
111 
112   virtual bool can_be_inline_klass(bool is_exact = false) {
113     return false;
114   }
115 
116   virtual bool can_be_inline_array_klass() {
117     return EnableValhalla && is_java_lang_Object();
118   }
119 
120   // Attempt to get a klass using this ciKlass's loader.
121   ciKlass* find_klass(ciSymbol* klass_name);
122   // Note:  To find a class from its name string, use ciSymbol::make,
123   // but consider adding to vmSymbols.hpp instead.
124 
125   // Get the instance of java.lang.Class corresponding to this klass.
126   ciInstance*            java_mirror();
127 
128   // Fetch Klass::modifier_flags.
129   jint                   modifier_flags();
130 
131   // Fetch Klass::access_flags.
132   jint                   access_flags();
133 
134   markWord prototype_header() const;
135 
136   // What kind of ciObject is this?
137   bool is_klass() const { return true; }
138 
139   virtual ciKlass* exact_klass() = 0;
140 
141   void print_name_on(outputStream* st);
142 
143   const char* external_name() const;
144 };
145 
146 #endif // SHARE_CI_CIKLASS_HPP