1 /* 2 * Copyright (C) 2008 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 #include "java_lang_System.h" 18 19 #include "common_throws.h" 20 #include "gc/accounting/card_table-inl.h" 21 #include "jni_internal.h" 22 #include "mirror/array.h" 23 #include "mirror/class.h" 24 #include "mirror/class-inl.h" 25 #include "mirror/object-inl.h" 26 #include "mirror/object_array-inl.h" 27 #include "scoped_fast_native_object_access.h" 28 29 namespace art { 30 31 /* 32 * We make guarantees about the atomicity of accesses to primitive variables. These guarantees 33 * also apply to elements of arrays. In particular, 8-bit, 16-bit, and 32-bit accesses must not 34 * cause "word tearing". Accesses to 64-bit array elements may be two 32-bit operations. 35 * References are never torn regardless of the number of bits used to represent them. 36 */ 37 38 static void ThrowArrayStoreException_NotAnArray(const char* identifier, mirror::Object* array) 39 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 40 std::string actualType(PrettyTypeOf(array)); 41 Thread* self = Thread::Current(); 42 self->ThrowNewExceptionF("Ljava/lang/ArrayStoreException;", 43 "%s of type %s is not an array", identifier, actualType.c_str()); 44 } 45 46 static void System_arraycopy(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, jobject javaDst, 47 jint dstPos, jint length) { 48 // The API is defined in terms of length, but length is somewhat overloaded so we use count. 49 const jint count = length; 50 ScopedFastNativeObjectAccess soa(env); 51 52 // Null pointer checks. 53 if (UNLIKELY(javaSrc == nullptr)) { 54 ThrowNullPointerException("src == null"); 55 return; 56 } 57 if (UNLIKELY(javaDst == nullptr)) { 58 ThrowNullPointerException("dst == null"); 59 return; 60 } 61 62 // Make sure source and destination are both arrays. 63 mirror::Object* srcObject = soa.Decode<mirror::Object*>(javaSrc); 64 if (UNLIKELY(!srcObject->IsArrayInstance())) { 65 ThrowArrayStoreException_NotAnArray("source", srcObject); 66 return; 67 } 68 mirror::Object* dstObject = soa.Decode<mirror::Object*>(javaDst); 69 if (UNLIKELY(!dstObject->IsArrayInstance())) { 70 ThrowArrayStoreException_NotAnArray("destination", dstObject); 71 return; 72 } 73 mirror::Array* srcArray = srcObject->AsArray(); 74 mirror::Array* dstArray = dstObject->AsArray(); 75 76 // Bounds checking. 77 if (UNLIKELY(srcPos < 0) || UNLIKELY(dstPos < 0) || UNLIKELY(count < 0) || 78 UNLIKELY(srcPos > srcArray->GetLength() - count) || 79 UNLIKELY(dstPos > dstArray->GetLength() - count)) { 80 soa.Self()->ThrowNewExceptionF("Ljava/lang/ArrayIndexOutOfBoundsException;", 81 "src.length=%d srcPos=%d dst.length=%d dstPos=%d length=%d", 82 srcArray->GetLength(), srcPos, dstArray->GetLength(), dstPos, 83 count); 84 return; 85 } 86 87 mirror::Class* dstComponentType = dstArray->GetClass()->GetComponentType(); 88 mirror::Class* srcComponentType = srcArray->GetClass()->GetComponentType(); 89 Primitive::Type dstComponentPrimitiveType = dstComponentType->GetPrimitiveType(); 90 91 if (LIKELY(srcComponentType == dstComponentType)) { 92 // Trivial assignability. 93 switch (dstComponentPrimitiveType) { 94 case Primitive::kPrimVoid: 95 LOG(FATAL) << "Unreachable, cannot have arrays of type void"; 96 UNREACHABLE(); 97 case Primitive::kPrimBoolean: 98 case Primitive::kPrimByte: 99 DCHECK_EQ(Primitive::ComponentSize(dstComponentPrimitiveType), 1U); 100 dstArray->AsByteSizedArray()->Memmove(dstPos, srcArray->AsByteSizedArray(), srcPos, count); 101 return; 102 case Primitive::kPrimChar: 103 case Primitive::kPrimShort: 104 DCHECK_EQ(Primitive::ComponentSize(dstComponentPrimitiveType), 2U); 105 dstArray->AsShortSizedArray()->Memmove(dstPos, srcArray->AsShortSizedArray(), srcPos, count); 106 return; 107 case Primitive::kPrimInt: 108 case Primitive::kPrimFloat: 109 DCHECK_EQ(Primitive::ComponentSize(dstComponentPrimitiveType), 4U); 110 dstArray->AsIntArray()->Memmove(dstPos, srcArray->AsIntArray(), srcPos, count); 111 return; 112 case Primitive::kPrimLong: 113 case Primitive::kPrimDouble: 114 DCHECK_EQ(Primitive::ComponentSize(dstComponentPrimitiveType), 8U); 115 dstArray->AsLongArray()->Memmove(dstPos, srcArray->AsLongArray(), srcPos, count); 116 return; 117 case Primitive::kPrimNot: { 118 mirror::ObjectArray<mirror::Object>* dstObjArray = dstArray->AsObjectArray<mirror::Object>(); 119 mirror::ObjectArray<mirror::Object>* srcObjArray = srcArray->AsObjectArray<mirror::Object>(); 120 dstObjArray->AssignableMemmove(dstPos, srcObjArray, srcPos, count); 121 return; 122 } 123 default: 124 LOG(FATAL) << "Unknown array type: " << PrettyTypeOf(srcArray); 125 UNREACHABLE(); 126 } 127 } 128 // If one of the arrays holds a primitive type the other array must hold the exact same type. 129 if (UNLIKELY((dstComponentPrimitiveType != Primitive::kPrimNot) || 130 srcComponentType->IsPrimitive())) { 131 std::string srcType(PrettyTypeOf(srcArray)); 132 std::string dstType(PrettyTypeOf(dstArray)); 133 soa.Self()->ThrowNewExceptionF("Ljava/lang/ArrayStoreException;", 134 "Incompatible types: src=%s, dst=%s", 135 srcType.c_str(), dstType.c_str()); 136 return; 137 } 138 // Arrays hold distinct types and so therefore can't alias - use memcpy instead of memmove. 139 mirror::ObjectArray<mirror::Object>* dstObjArray = dstArray->AsObjectArray<mirror::Object>(); 140 mirror::ObjectArray<mirror::Object>* srcObjArray = srcArray->AsObjectArray<mirror::Object>(); 141 // If we're assigning into say Object[] then we don't need per element checks. 142 if (dstComponentType->IsAssignableFrom(srcComponentType)) { 143 dstObjArray->AssignableMemcpy(dstPos, srcObjArray, srcPos, count); 144 return; 145 } 146 dstObjArray->AssignableCheckingMemcpy(dstPos, srcObjArray, srcPos, count, true); 147 } 148 149 // Template to convert general array to that of its specific primitive type. 150 template <typename T> 151 inline T* AsPrimitiveArray(mirror::Array* array) { 152 return down_cast<T*>(array); 153 } 154 155 template <typename T, Primitive::Type kPrimType> 156 inline void System_arraycopyTUnchecked(JNIEnv* env, jobject javaSrc, jint srcPos, 157 jobject javaDst, jint dstPos, jint count) { 158 ScopedFastNativeObjectAccess soa(env); 159 mirror::Object* srcObject = soa.Decode<mirror::Object*>(javaSrc); 160 mirror::Object* dstObject = soa.Decode<mirror::Object*>(javaDst); 161 DCHECK(dstObject != nullptr); 162 mirror::Array* srcArray = srcObject->AsArray(); 163 mirror::Array* dstArray = dstObject->AsArray(); 164 DCHECK_GE(count, 0); 165 DCHECK_EQ(srcArray->GetClass(), dstArray->GetClass()); 166 DCHECK_EQ(srcArray->GetClass()->GetComponentType()->GetPrimitiveType(), kPrimType); 167 AsPrimitiveArray<T>(dstArray)->Memmove(dstPos, AsPrimitiveArray<T>(srcArray), srcPos, count); 168 } 169 170 static void System_arraycopyCharUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 171 jobject javaDst, jint dstPos, jint count) { 172 System_arraycopyTUnchecked<mirror::CharArray, Primitive::kPrimChar>(env, javaSrc, srcPos, 173 javaDst, dstPos, count); 174 } 175 176 static void System_arraycopyByteUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 177 jobject javaDst, jint dstPos, jint count) { 178 System_arraycopyTUnchecked<mirror::ByteArray, Primitive::kPrimByte>(env, javaSrc, srcPos, 179 javaDst, dstPos, count); 180 } 181 182 static void System_arraycopyShortUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 183 jobject javaDst, jint dstPos, jint count) { 184 System_arraycopyTUnchecked<mirror::ShortArray, Primitive::kPrimShort>(env, javaSrc, srcPos, 185 javaDst, dstPos, count); 186 } 187 188 static void System_arraycopyIntUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 189 jobject javaDst, jint dstPos, jint count) { 190 System_arraycopyTUnchecked<mirror::IntArray, Primitive::kPrimInt>(env, javaSrc, srcPos, 191 javaDst, dstPos, count); 192 } 193 194 static void System_arraycopyLongUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 195 jobject javaDst, jint dstPos, jint count) { 196 System_arraycopyTUnchecked<mirror::LongArray, Primitive::kPrimLong>(env, javaSrc, srcPos, 197 javaDst, dstPos, count); 198 } 199 200 static void System_arraycopyFloatUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 201 jobject javaDst, jint dstPos, jint count) { 202 System_arraycopyTUnchecked<mirror::FloatArray, Primitive::kPrimFloat>(env, javaSrc, srcPos, 203 javaDst, dstPos, count); 204 } 205 206 static void System_arraycopyDoubleUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 207 jobject javaDst, jint dstPos, jint count) { 208 System_arraycopyTUnchecked<mirror::DoubleArray, Primitive::kPrimDouble>(env, javaSrc, srcPos, 209 javaDst, dstPos, count); 210 } 211 212 static void System_arraycopyBooleanUnchecked(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, 213 jobject javaDst, jint dstPos, jint count) { 214 System_arraycopyTUnchecked<mirror::BooleanArray, Primitive::kPrimBoolean>(env, javaSrc, srcPos, 215 javaDst, dstPos, count); 216 } 217 218 static jint System_identityHashCode(JNIEnv* env, jclass, jobject javaObject) { 219 if (UNLIKELY(javaObject == nullptr)) { 220 return 0; 221 } 222 ScopedFastNativeObjectAccess soa(env); 223 mirror::Object* o = soa.Decode<mirror::Object*>(javaObject); 224 return static_cast<jint>(o->IdentityHashCode()); 225 } 226 227 static JNINativeMethod gMethods[] = { 228 NATIVE_METHOD(System, arraycopy, "!(Ljava/lang/Object;ILjava/lang/Object;II)V"), 229 NATIVE_METHOD(System, arraycopyCharUnchecked, "!([CI[CII)V"), 230 NATIVE_METHOD(System, arraycopyByteUnchecked, "!([BI[BII)V"), 231 NATIVE_METHOD(System, arraycopyShortUnchecked, "!([SI[SII)V"), 232 NATIVE_METHOD(System, arraycopyIntUnchecked, "!([II[III)V"), 233 NATIVE_METHOD(System, arraycopyLongUnchecked, "!([JI[JII)V"), 234 NATIVE_METHOD(System, arraycopyFloatUnchecked, "!([FI[FII)V"), 235 NATIVE_METHOD(System, arraycopyDoubleUnchecked, "!([DI[DII)V"), 236 NATIVE_METHOD(System, arraycopyBooleanUnchecked, "!([ZI[ZII)V"), 237 NATIVE_METHOD(System, identityHashCode, "!(Ljava/lang/Object;)I"), 238 }; 239 240 void register_java_lang_System(JNIEnv* env) { 241 REGISTER_NATIVE_METHODS("java/lang/System"); 242 } 243 244 } // namespace art 245
