1 /*
   2  * Copyright (c) 2000, 2019, 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.
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  23  */
  24 
  25 #ifndef SHARE_CI_CITYPE_HPP
  26 #define SHARE_CI_CITYPE_HPP
  27 
  28 #include "ci/ciMetadata.hpp"
  29 
  30 // ciType
  31 //
  32 // This class represents either a class (T_OBJECT), value (T_VALUETYPE),
  33 // array (T_ARRAY), or one of the primitive types such as T_INT.
  34 class ciType : public ciMetadata {
  35   CI_PACKAGE_ACCESS
  36   friend class ciKlass;
  37   friend class ciReturnAddress;
  38   friend class ciWrapper;
  39 
  40 private:
  41   BasicType _basic_type;
  42 
  43   ciType(BasicType t);     // for primitive and unloaded types
  44   ciType(Klass* k);        // for subclasses (reference types)
  45 
  46   const char* type_string() { return "ciType"; }
  47 
  48   void print_impl(outputStream* st);
  49 
  50   // Distinguished instances of primitive ciTypes..
  51   static ciType* _basic_types[T_CONFLICT+1];
  52 
  53 public:
  54   BasicType basic_type() const              { return _basic_type; }
  55 
  56   // Returns true iff the types are identical, or if both are klasses
  57   // and the is_subtype_of relation holds between the klasses.
  58   bool is_subtype_of(ciType* type);
  59 
  60   // Get the instance of java.lang.Class corresponding to this type.
  61   // There are mirrors for instance, array, and primitive types (incl. void).
  62   virtual ciInstance*    java_mirror();
  63 
  64   // Get the class which "boxes" (or "wraps") values of this type.
  65   // Example:  short is boxed by java.lang.Short, etc.
  66   // Returns self if it is a reference type.
  67   // Returns NULL for void, since null is used in such cases.
  68   ciKlass*  box_klass();
  69 
  70   // Returns true if this is not a klass or array (i.e., not a reference type).
  71   bool is_primitive_type() const            { return basic_type() != T_OBJECT && basic_type() != T_ARRAY && basic_type() != T_VALUETYPE; }
  72   int size() const                          { return type2size[basic_type()]; }
  73   bool is_void() const                      { return basic_type() == T_VOID; }
  74   bool is_one_word() const                  { return size() == 1; }
  75   bool is_two_word() const                  { return size() == 2; }
  76 
  77   // What kind of ciObject is this?
  78   bool is_type() const                      { return true; }
  79   bool is_classless() const                 { return is_primitive_type(); }
  80 
  81   virtual ciType*     unwrap()              { return this; }
  82   virtual bool is_never_null() const        { return false; }
  83 
  84   const char* name();
  85   virtual void print_name_on(outputStream* st);
  86   void print_name() {
  87     print_name_on(tty);
  88   }
  89 
  90   static ciType* make(BasicType t);
  91 };
  92 
  93 
  94 // ciReturnAddress
  95 //
  96 // This class represents the type of a specific return address in the
  97 // bytecodes.
  98 class ciReturnAddress : public ciType {
  99   CI_PACKAGE_ACCESS
 100 
 101 private:
 102   // The bci of this return address.
 103   int _bci;
 104 
 105   ciReturnAddress(int bci);
 106 
 107   const char* type_string() { return "ciReturnAddress"; }
 108 
 109   void print_impl(outputStream* st);
 110 
 111 public:
 112   bool is_return_address() const { return true; }
 113 
 114   int  bci() { return _bci; }
 115 
 116   static ciReturnAddress* make(int bci);
 117 };
 118 
 119 // ciWrapper
 120 //
 121 // This class wraps another type to carry additional information like nullability.
 122 // Should only be instantiated and used by ciTypeFlow and ciSignature.
 123 class ciWrapper : public ciType {
 124   CI_PACKAGE_ACCESS
 125 
 126 private:
 127   ciType* _type;
 128   bool _never_null;
 129 
 130   ciWrapper(ciType* type, bool never_null) : ciType(type->basic_type()) {
 131     assert(type->is_valuetype(), "should only be used for value types");
 132     _type = type;
 133     _never_null = never_null;
 134   }
 135 
 136   const char* type_string() { return "ciWrapper"; }
 137 
 138   void print_impl(outputStream* st) { _type->print_impl(st); }
 139 
 140 public:
 141   bool    is_wrapper() const { return true; }
 142 
 143   ciType*     unwrap()       { return _type; }
 144   bool is_never_null() const { return _never_null; }
 145 };
 146 
 147 #endif // SHARE_CI_CITYPE_HPP