Nikolay Igotti
105 lines
3.4 KiB
C++
105 lines
3.4 KiB
C++
/*
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* Copyright 2010-2018 JetBrains s.r.o.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "Atomic.h"
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#include "Common.h"
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#include "Exceptions.h"
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#include "Memory.h"
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#include "Types.h"
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namespace {
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struct AtomicReferenceLayout {
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KRef value_;
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KInt lock_;
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};
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template <typename T> T addAndGetImpl(KRef thiz, T delta) {
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volatile T* location = reinterpret_cast<volatile T*>(thiz + 1);
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return atomicAdd(location, delta);
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}
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template <typename T> T compareAndSwapImpl(KRef thiz, T expectedValue, T newValue) {
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volatile T* location = reinterpret_cast<volatile T*>(thiz + 1);
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return compareAndSwap(location, expectedValue, newValue);
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}
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inline AtomicReferenceLayout* asAtomicReference(KRef thiz) {
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return reinterpret_cast<AtomicReferenceLayout*>(thiz + 1);
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}
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} // namespace
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extern "C" {
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KInt Kotlin_AtomicInt_addAndGet(KRef thiz, KInt delta) {
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return addAndGetImpl(thiz, delta);
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}
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KInt Kotlin_AtomicInt_compareAndSwap(KRef thiz, KInt expectedValue, KInt newValue) {
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return compareAndSwapImpl(thiz, expectedValue, newValue);
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}
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KLong Kotlin_AtomicLong_addAndGet(KRef thiz, KLong delta) {
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return addAndGetImpl(thiz, delta);
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}
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KLong Kotlin_AtomicLong_compareAndSwap(KRef thiz, KLong expectedValue, KLong newValue) {
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#ifdef __mips
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// Potentially huge performance penalty, but correct.
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// TODO: reconsider, once target MIPS can do proper 64-bit CAS.
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static int lock = 0;
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while (compareAndSwap(&lock, 0, 1) != 0);
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KLong* address = reinterpret_cast<KLong*>(thiz + 1);
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KLong old = *address;
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if (old == expectedValue) {
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*address = newValue;
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}
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compareAndSwap(&lock, 1, 0);
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return old;
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#else
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return compareAndSwapImpl(thiz, expectedValue, newValue);
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#endif
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}
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KNativePtr Kotlin_AtomicNativePtr_compareAndSwap(KRef thiz, KNativePtr expectedValue, KNativePtr newValue) {
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return compareAndSwapImpl(thiz, expectedValue, newValue);
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}
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void Kotlin_AtomicReference_checkIfFrozen(KRef value) {
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if (value != nullptr && !value->container()->permanentOrFrozen()) {
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ThrowInvalidMutabilityException(value);
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}
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}
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OBJ_GETTER(Kotlin_AtomicReference_compareAndSwap, KRef thiz, KRef expectedValue, KRef newValue) {
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Kotlin_AtomicReference_checkIfFrozen(newValue);
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// See Kotlin_AtomicReference_get() for explanations, why locking is needed.
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AtomicReferenceLayout* ref = asAtomicReference(thiz);
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RETURN_RESULT_OF(SwapRefLocked, &ref->value_, expectedValue, newValue, &ref->lock_);
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}
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OBJ_GETTER(Kotlin_AtomicReference_get, KRef thiz) {
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// Here we must take a lock to prevent race when value, while taken here, is CASed and immediately
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// destroyed by an another thread. AtomicReference no longer holds such an object, so if we got
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// rescheduled unluckily, between the moment value is read from the field and RC is incremented,
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// object may go away.
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AtomicReferenceLayout* ref = asAtomicReference(thiz);
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RETURN_RESULT_OF(ReadRefLocked, &ref->value_, &ref->lock_);
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}
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} // extern "C"
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