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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_MIRROR_OBJECT_H_
     18 #define ART_RUNTIME_MIRROR_OBJECT_H_
     19 
     20 #include "base/casts.h"
     21 #include "base/logging.h"
     22 #include "base/macros.h"
     23 #include "cutils/atomic-inline.h"
     24 #include "offsets.h"
     25 
     26 namespace art {
     27 
     28 class ImageWriter;
     29 struct ObjectOffsets;
     30 class Thread;
     31 
     32 namespace mirror {
     33 
     34 class ArtField;
     35 class ArtMethod;
     36 class Array;
     37 class Class;
     38 template<class T> class ObjectArray;
     39 template<class T> class PrimitiveArray;
     40 typedef PrimitiveArray<uint8_t> BooleanArray;
     41 typedef PrimitiveArray<int8_t> ByteArray;
     42 typedef PrimitiveArray<uint16_t> CharArray;
     43 typedef PrimitiveArray<double> DoubleArray;
     44 typedef PrimitiveArray<float> FloatArray;
     45 typedef PrimitiveArray<int32_t> IntArray;
     46 typedef PrimitiveArray<int64_t> LongArray;
     47 typedef PrimitiveArray<int16_t> ShortArray;
     48 class String;
     49 class Throwable;
     50 
     51 // Classes shared with the managed side of the world need to be packed so that they don't have
     52 // extra platform specific padding.
     53 #define MANAGED PACKED(4)
     54 
     55 // Fields within mirror objects aren't accessed directly so that the appropriate amount of
     56 // handshaking is done with GC (for example, read and write barriers). This macro is used to
     57 // compute an offset for the Set/Get methods defined in Object that can safely access fields.
     58 #define OFFSET_OF_OBJECT_MEMBER(type, field) \
     59     MemberOffset(OFFSETOF_MEMBER(type, field))
     60 
     61 const bool kCheckFieldAssignments = false;
     62 
     63 // C++ mirror of java.lang.Object
     64 class MANAGED Object {
     65  public:
     66   static MemberOffset ClassOffset() {
     67     return OFFSET_OF_OBJECT_MEMBER(Object, klass_);
     68   }
     69 
     70   Class* GetClass() const;
     71 
     72   void SetClass(Class* new_klass);
     73 
     74   // The verifier treats all interfaces as java.lang.Object and relies on runtime checks in
     75   // invoke-interface to detect incompatible interface types.
     76   bool VerifierInstanceOf(const Class* klass) const
     77         SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     78 
     79   bool InstanceOf(const Class* klass) const
     80       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     81 
     82   size_t SizeOf() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     83 
     84   Object* Clone(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     85 
     86   int32_t IdentityHashCode() const {
     87 #ifdef MOVING_GARBAGE_COLLECTOR
     88     // TODO: we'll need to use the Object's internal concept of identity
     89     UNIMPLEMENTED(FATAL);
     90 #endif
     91     return reinterpret_cast<int32_t>(this);
     92   }
     93 
     94   static MemberOffset MonitorOffset() {
     95     return OFFSET_OF_OBJECT_MEMBER(Object, monitor_);
     96   }
     97 
     98   volatile int32_t* GetRawLockWordAddress() {
     99     byte* raw_addr = reinterpret_cast<byte*>(this) +
    100         OFFSET_OF_OBJECT_MEMBER(Object, monitor_).Int32Value();
    101     int32_t* word_addr = reinterpret_cast<int32_t*>(raw_addr);
    102     return const_cast<volatile int32_t*>(word_addr);
    103   }
    104 
    105   uint32_t GetThinLockId();
    106 
    107   void MonitorEnter(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
    108       EXCLUSIVE_LOCK_FUNCTION(monitor_lock_);
    109 
    110   bool MonitorExit(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
    111       UNLOCK_FUNCTION(monitor_lock_);
    112 
    113   void Notify(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    114 
    115   void NotifyAll(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    116 
    117   void Wait(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    118 
    119   void Wait(Thread* self, int64_t timeout, int32_t nanos) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    120 
    121   bool IsClass() const;
    122 
    123   Class* AsClass();
    124 
    125   const Class* AsClass() const;
    126 
    127   bool IsObjectArray() const;
    128 
    129   template<class T>
    130   ObjectArray<T>* AsObjectArray();
    131 
    132   template<class T>
    133   const ObjectArray<T>* AsObjectArray() const;
    134 
    135   bool IsArrayInstance() const;
    136 
    137   Array* AsArray();
    138 
    139   const Array* AsArray() const;
    140 
    141   BooleanArray* AsBooleanArray();
    142   ByteArray* AsByteArray();
    143   CharArray* AsCharArray();
    144   ShortArray* AsShortArray();
    145   IntArray* AsIntArray();
    146   LongArray* AsLongArray();
    147 
    148   String* AsString();
    149 
    150   Throwable* AsThrowable() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    151 
    152   bool IsArtMethod() const;
    153 
    154   ArtMethod* AsArtMethod();
    155 
    156   const ArtMethod* AsArtMethod() const;
    157 
    158   bool IsArtField() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    159 
    160   ArtField* AsArtField() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    161 
    162   const ArtField* AsArtField() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    163 
    164   bool IsReferenceInstance() const;
    165 
    166   bool IsWeakReferenceInstance() const;
    167 
    168   bool IsSoftReferenceInstance() const;
    169 
    170   bool IsFinalizerReferenceInstance() const;
    171 
    172   bool IsPhantomReferenceInstance() const;
    173 
    174   // Accessors for Java type fields
    175   template<class T>
    176   T GetFieldObject(MemberOffset field_offset, bool is_volatile) const {
    177     T result = reinterpret_cast<T>(GetField32(field_offset, is_volatile));
    178     VerifyObject(result);
    179     return result;
    180   }
    181 
    182   void SetFieldObject(MemberOffset field_offset, const Object* new_value, bool is_volatile,
    183                       bool this_is_valid = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    184     VerifyObject(new_value);
    185     SetField32(field_offset, reinterpret_cast<uint32_t>(new_value), is_volatile, this_is_valid);
    186     if (new_value != NULL) {
    187       CheckFieldAssignment(field_offset, new_value);
    188       WriteBarrierField(this, field_offset, new_value);
    189     }
    190   }
    191 
    192   uint32_t GetField32(MemberOffset field_offset, bool is_volatile) const {
    193     VerifyObject(this);
    194     const byte* raw_addr = reinterpret_cast<const byte*>(this) + field_offset.Int32Value();
    195     const int32_t* word_addr = reinterpret_cast<const int32_t*>(raw_addr);
    196     if (UNLIKELY(is_volatile)) {
    197       return android_atomic_acquire_load(word_addr);
    198     } else {
    199       return *word_addr;
    200     }
    201   }
    202 
    203   void SetField32(MemberOffset field_offset, uint32_t new_value, bool is_volatile,
    204                   bool this_is_valid = true) {
    205     if (this_is_valid) {
    206       VerifyObject(this);
    207     }
    208     byte* raw_addr = reinterpret_cast<byte*>(this) + field_offset.Int32Value();
    209     uint32_t* word_addr = reinterpret_cast<uint32_t*>(raw_addr);
    210     if (UNLIKELY(is_volatile)) {
    211       /*
    212        * TODO: add an android_atomic_synchronization_store() function and
    213        * use it in the 32-bit volatile set handlers.  On some platforms we
    214        * can use a fast atomic instruction and avoid the barriers.
    215        */
    216       ANDROID_MEMBAR_STORE();
    217       *word_addr = new_value;
    218       ANDROID_MEMBAR_FULL();
    219     } else {
    220       *word_addr = new_value;
    221     }
    222   }
    223 
    224   uint64_t GetField64(MemberOffset field_offset, bool is_volatile) const;
    225 
    226   void SetField64(MemberOffset field_offset, uint64_t new_value, bool is_volatile);
    227 
    228  protected:
    229   // Accessors for non-Java type fields
    230   template<class T>
    231   T GetFieldPtr(MemberOffset field_offset, bool is_volatile) const {
    232     return reinterpret_cast<T>(GetField32(field_offset, is_volatile));
    233   }
    234 
    235   template<typename T>
    236   void SetFieldPtr(MemberOffset field_offset, T new_value, bool is_volatile, bool this_is_valid = true) {
    237     SetField32(field_offset, reinterpret_cast<uint32_t>(new_value), is_volatile, this_is_valid);
    238   }
    239 
    240  private:
    241   static void VerifyObject(const Object* obj) ALWAYS_INLINE;
    242 
    243   // Verify the type correctness of stores to fields.
    244   void CheckFieldAssignmentImpl(MemberOffset field_offset, const Object* new_value)
    245       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    246   void CheckFieldAssignment(MemberOffset field_offset, const Object* new_value)
    247       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    248     if (kCheckFieldAssignments) {
    249       CheckFieldAssignmentImpl(field_offset, new_value);
    250     }
    251   }
    252 
    253   // Write barrier called post update to a reference bearing field.
    254   static void WriteBarrierField(const Object* dst, MemberOffset offset, const Object* new_value);
    255 
    256   Class* klass_;
    257 
    258   uint32_t monitor_;
    259 
    260   friend class art::ImageWriter;
    261   friend struct art::ObjectOffsets;  // for verifying offset information
    262   DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
    263 };
    264 
    265 }  // namespace mirror
    266 }  // namespace art
    267 
    268 #endif  // ART_RUNTIME_MIRROR_OBJECT_H_
    269