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Diffstat (limited to 'src/native/java_lang_System.cc')
| -rw-r--r-- | src/native/java_lang_System.cc | 334 |
1 files changed, 0 insertions, 334 deletions
diff --git a/src/native/java_lang_System.cc b/src/native/java_lang_System.cc deleted file mode 100644 index 2462f2fd8e..0000000000 --- a/src/native/java_lang_System.cc +++ /dev/null @@ -1,334 +0,0 @@ -/* - * Copyright (C) 2008 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#include "common_throws.h" -#include "gc/accounting/card_table-inl.h" -#include "jni_internal.h" -#include "mirror/array.h" -#include "mirror/class.h" -#include "mirror/class-inl.h" -#include "mirror/object-inl.h" -#include "mirror/object_array-inl.h" -#include "scoped_thread_state_change.h" - -/* - * We make guarantees about the atomicity of accesses to primitive - * variables. These guarantees also apply to elements of arrays. - * In particular, 8-bit, 16-bit, and 32-bit accesses must be atomic and - * must not cause "word tearing". Accesses to 64-bit array elements must - * either be atomic or treated as two 32-bit operations. References are - * always read and written atomically, regardless of the number of bits - * used to represent them. - * - * We can't rely on standard libc functions like memcpy(3) and memmove(3) - * in our implementation of System.arraycopy, because they may copy - * byte-by-byte (either for the full run or for "unaligned" parts at the - * start or end). We need to use functions that guarantee 16-bit or 32-bit - * atomicity as appropriate. - * - * System.arraycopy() is heavily used, so having an efficient implementation - * is important. The bionic libc provides a platform-optimized memory move - * function that should be used when possible. If it's not available, - * the trivial "reference implementation" versions below can be used until - * a proper version can be written. - * - * For these functions, The caller must guarantee that dst/src are aligned - * appropriately for the element type, and that n is a multiple of the - * element size. - */ - -/* - * Works like memmove(), except: - * - if all arguments are at least 32-bit aligned, we guarantee that we - * will use operations that preserve atomicity of 32-bit values - * - if not, we guarantee atomicity of 16-bit values - * - * If all three arguments are not at least 16-bit aligned, the behavior - * of this function is undefined. (We could remove this restriction by - * testing for unaligned values and punting to memmove(), but that's - * not currently useful.) - * - * TODO: add loop for 64-bit alignment - * TODO: use __builtin_prefetch - * TODO: write ARM/MIPS/x86 optimized versions - */ -void MemmoveWords(void* dst, const void* src, size_t n) { - DCHECK_EQ((((uintptr_t) dst | (uintptr_t) src | n) & 0x01), 0U); - - char* d = reinterpret_cast<char*>(dst); - const char* s = reinterpret_cast<const char*>(src); - size_t copyCount; - - // If the source and destination pointers are the same, this is - // an expensive no-op. Testing for an empty move now allows us - // to skip a check later. - if (n == 0 || d == s) { - return; - } - - // Determine if the source and destination buffers will overlap if - // we copy data forward (i.e. *dst++ = *src++). - // - // It's okay if the destination buffer starts before the source and - // there is some overlap, because the reader is always ahead of the - // writer. - if (LIKELY((d < s) || ((size_t)(d - s) >= n))) { - // Copy forward. We prefer 32-bit loads and stores even for 16-bit - // data, so sort that out. - if (((reinterpret_cast<uintptr_t>(d) | reinterpret_cast<uintptr_t>(s)) & 0x03) != 0) { - // Not 32-bit aligned. Two possibilities: - // (1) Congruent, we can align to 32-bit by copying one 16-bit val - // (2) Non-congruent, we can do one of: - // a. copy whole buffer as a series of 16-bit values - // b. load/store 32 bits, using shifts to ensure alignment - // c. just copy the as 32-bit values and assume the CPU - // will do a reasonable job - // - // We're currently using (a), which is suboptimal. - if (((reinterpret_cast<uintptr_t>(d) ^ reinterpret_cast<uintptr_t>(s)) & 0x03) != 0) { - copyCount = n; - } else { - copyCount = 2; - } - n -= copyCount; - copyCount /= sizeof(uint16_t); - - while (copyCount--) { - *reinterpret_cast<uint16_t*>(d) = *reinterpret_cast<const uint16_t*>(s); - d += sizeof(uint16_t); - s += sizeof(uint16_t); - } - } - - // Copy 32-bit aligned words. - copyCount = n / sizeof(uint32_t); - while (copyCount--) { - *reinterpret_cast<uint32_t*>(d) = *reinterpret_cast<const uint32_t*>(s); - d += sizeof(uint32_t); - s += sizeof(uint32_t); - } - - // Check for leftovers. Either we finished exactly, or we have one remaining 16-bit chunk. - if ((n & 0x02) != 0) { - *(uint16_t*)d = *(uint16_t*)s; - } - } else { - // Copy backward, starting at the end. - d += n; - s += n; - - if (((reinterpret_cast<uintptr_t>(d) | reinterpret_cast<uintptr_t>(s)) & 0x03) != 0) { - // try for 32-bit alignment. - if (((reinterpret_cast<uintptr_t>(d) ^ reinterpret_cast<uintptr_t>(s)) & 0x03) != 0) { - copyCount = n; - } else { - copyCount = 2; - } - n -= copyCount; - copyCount /= sizeof(uint16_t); - - while (copyCount--) { - d -= sizeof(uint16_t); - s -= sizeof(uint16_t); - *reinterpret_cast<uint16_t*>(d) = *reinterpret_cast<const uint16_t*>(s); - } - } - - // Copy 32-bit aligned words. - copyCount = n / sizeof(uint32_t); - while (copyCount--) { - d -= sizeof(uint32_t); - s -= sizeof(uint32_t); - *reinterpret_cast<uint32_t*>(d) = *reinterpret_cast<const uint32_t*>(s); - } - - // Copy leftovers. - if ((n & 0x02) != 0) { - d -= sizeof(uint16_t); - s -= sizeof(uint16_t); - *reinterpret_cast<uint16_t*>(d) = *reinterpret_cast<const uint16_t*>(s); - } - } -} - -#define move16 MemmoveWords -#define move32 MemmoveWords - -namespace art { - -static void ThrowArrayStoreException_NotAnArray(const char* identifier, mirror::Object* array) - SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { - std::string actualType(PrettyTypeOf(array)); - Thread* self = Thread::Current(); - ThrowLocation throw_location = self->GetCurrentLocationForThrow(); - self->ThrowNewExceptionF(throw_location, "Ljava/lang/ArrayStoreException;", - "%s of type %s is not an array", identifier, actualType.c_str()); -} - -static void System_arraycopy(JNIEnv* env, jclass, jobject javaSrc, jint srcPos, jobject javaDst, jint dstPos, jint length) { - ScopedObjectAccess soa(env); - - // Null pointer checks. - if (UNLIKELY(javaSrc == NULL)) { - ThrowNullPointerException(NULL, "src == null"); - return; - } - if (UNLIKELY(javaDst == NULL)) { - ThrowNullPointerException(NULL, "dst == null"); - return; - } - - // Make sure source and destination are both arrays. - mirror::Object* srcObject = soa.Decode<mirror::Object*>(javaSrc); - mirror::Object* dstObject = soa.Decode<mirror::Object*>(javaDst); - if (UNLIKELY(!srcObject->IsArrayInstance())) { - ThrowArrayStoreException_NotAnArray("source", srcObject); - return; - } - if (UNLIKELY(!dstObject->IsArrayInstance())) { - ThrowArrayStoreException_NotAnArray("destination", dstObject); - return; - } - mirror::Array* srcArray = srcObject->AsArray(); - mirror::Array* dstArray = dstObject->AsArray(); - mirror::Class* srcComponentType = srcArray->GetClass()->GetComponentType(); - mirror::Class* dstComponentType = dstArray->GetClass()->GetComponentType(); - - // Bounds checking. - if (UNLIKELY(srcPos < 0 || dstPos < 0 || length < 0 || srcPos > srcArray->GetLength() - length || dstPos > dstArray->GetLength() - length)) { - ThrowLocation throw_location = soa.Self()->GetCurrentLocationForThrow(); - soa.Self()->ThrowNewExceptionF(throw_location, "Ljava/lang/ArrayIndexOutOfBoundsException;", - "src.length=%d srcPos=%d dst.length=%d dstPos=%d length=%d", - srcArray->GetLength(), srcPos, dstArray->GetLength(), dstPos, length); - return; - } - - // Handle primitive arrays. - if (srcComponentType->IsPrimitive() || dstComponentType->IsPrimitive()) { - // If one of the arrays holds a primitive type the other array must hold the exact same type. - if (UNLIKELY(srcComponentType != dstComponentType)) { - std::string srcType(PrettyTypeOf(srcArray)); - std::string dstType(PrettyTypeOf(dstArray)); - ThrowLocation throw_location = soa.Self()->GetCurrentLocationForThrow(); - soa.Self()->ThrowNewExceptionF(throw_location, "Ljava/lang/ArrayStoreException;", - "Incompatible types: src=%s, dst=%s", - srcType.c_str(), dstType.c_str()); - return; - } - - size_t width = srcArray->GetClass()->GetComponentSize(); - uint8_t* dstBytes = reinterpret_cast<uint8_t*>(dstArray->GetRawData(width)); - const uint8_t* srcBytes = reinterpret_cast<const uint8_t*>(srcArray->GetRawData(width)); - - switch (width) { - case 1: - memmove(dstBytes + dstPos, srcBytes + srcPos, length); - break; - case 2: - move16(dstBytes + dstPos * 2, srcBytes + srcPos * 2, length * 2); - break; - case 4: - move32(dstBytes + dstPos * 4, srcBytes + srcPos * 4, length * 4); - break; - case 8: - // We don't need to guarantee atomicity of the entire 64-bit word. - move32(dstBytes + dstPos * 8, srcBytes + srcPos * 8, length * 8); - break; - default: - LOG(FATAL) << "Unknown primitive array type: " << PrettyTypeOf(srcArray); - } - - return; - } - - // Neither class is primitive. Are the types trivially compatible? - const size_t width = sizeof(mirror::Object*); - uint8_t* dstBytes = reinterpret_cast<uint8_t*>(dstArray->GetRawData(width)); - const uint8_t* srcBytes = reinterpret_cast<const uint8_t*>(srcArray->GetRawData(width)); - if (dstArray == srcArray || dstComponentType->IsAssignableFrom(srcComponentType)) { - // Yes. Bulk copy. - COMPILE_ASSERT(sizeof(width) == sizeof(uint32_t), move32_assumes_Object_references_are_32_bit); - move32(dstBytes + dstPos * width, srcBytes + srcPos * width, length * width); - Runtime::Current()->GetHeap()->WriteBarrierArray(dstArray, dstPos, length); - return; - } - - // The arrays are not trivially compatible. However, we may still be able to copy some or all of - // the elements if the source objects are compatible (for example, copying an Object[] to - // String[], the Objects being copied might actually be Strings). - // We can't do a bulk move because that would introduce a check-use race condition, so we copy - // elements one by one. - - // We already dealt with overlapping copies, so we don't need to cope with that case below. - CHECK_NE(dstArray, srcArray); - - mirror::Object* const * srcObjects = - reinterpret_cast<mirror::Object* const *>(srcBytes + srcPos * width); - mirror::Object** dstObjects = reinterpret_cast<mirror::Object**>(dstBytes + dstPos * width); - mirror::Class* dstClass = dstArray->GetClass()->GetComponentType(); - - // We want to avoid redundant IsAssignableFrom checks where possible, so we cache a class that - // we know is assignable to the destination array's component type. - mirror::Class* lastAssignableElementClass = dstClass; - - mirror::Object* o = NULL; - int i = 0; - for (; i < length; ++i) { - o = srcObjects[i]; - if (o != NULL) { - mirror::Class* oClass = o->GetClass(); - if (lastAssignableElementClass == oClass) { - dstObjects[i] = o; - } else if (dstClass->IsAssignableFrom(oClass)) { - lastAssignableElementClass = oClass; - dstObjects[i] = o; - } else { - // Can't put this element into the array. - break; - } - } else { - dstObjects[i] = NULL; - } - } - - Runtime::Current()->GetHeap()->WriteBarrierArray(dstArray, dstPos, length); - if (UNLIKELY(i != length)) { - std::string actualSrcType(PrettyTypeOf(o)); - std::string dstType(PrettyTypeOf(dstArray)); - ThrowLocation throw_location = soa.Self()->GetCurrentLocationForThrow(); - soa.Self()->ThrowNewExceptionF(throw_location, "Ljava/lang/ArrayStoreException;", - "source[%d] of type %s cannot be stored in destination array of type %s", - srcPos + i, actualSrcType.c_str(), dstType.c_str()); - return; - } -} - -static jint System_identityHashCode(JNIEnv* env, jclass, jobject javaObject) { - ScopedObjectAccess soa(env); - mirror::Object* o = soa.Decode<mirror::Object*>(javaObject); - return static_cast<jint>(o->IdentityHashCode()); -} - -static JNINativeMethod gMethods[] = { - NATIVE_METHOD(System, arraycopy, "(Ljava/lang/Object;ILjava/lang/Object;II)V"), - NATIVE_METHOD(System, identityHashCode, "(Ljava/lang/Object;)I"), -}; - -void register_java_lang_System(JNIEnv* env) { - REGISTER_NATIVE_METHODS("java/lang/System"); -} - -} // namespace art |