diff options
Diffstat (limited to 'lib/pure/concurrency/atomics.nim')
| -rw-r--r-- | lib/pure/concurrency/atomics.nim | 148 |
1 files changed, 101 insertions, 47 deletions
diff --git a/lib/pure/concurrency/atomics.nim b/lib/pure/concurrency/atomics.nim index 29491f68c..818f1b37a 100644 --- a/lib/pure/concurrency/atomics.nim +++ b/lib/pure/concurrency/atomics.nim @@ -10,10 +10,50 @@ ## Types and operations for atomic operations and lockless algorithms. ## ## Unstable API. - -import macros - -when defined(cpp) or defined(nimdoc): +## +## By default, C++ uses C11 atomic primitives. To use C++ `std::atomic`, +## `-d:nimUseCppAtomics` can be defined. + +runnableExamples: + # Atomic + var loc: Atomic[int] + loc.store(4) + assert loc.load == 4 + loc.store(2) + assert loc.load(moRelaxed) == 2 + loc.store(9) + assert loc.load(moAcquire) == 9 + loc.store(0, moRelease) + assert loc.load == 0 + + assert loc.exchange(7) == 0 + assert loc.load == 7 + + var expected = 7 + assert loc.compareExchange(expected, 5, moRelaxed, moRelaxed) + assert expected == 7 + assert loc.load == 5 + + assert not loc.compareExchange(expected, 12, moRelaxed, moRelaxed) + assert expected == 5 + assert loc.load == 5 + + assert loc.fetchAdd(1) == 5 + assert loc.fetchAdd(2) == 6 + assert loc.fetchSub(3) == 8 + + loc.atomicInc(1) + assert loc.load == 6 + + # AtomicFlag + var flag: AtomicFlag + + assert not flag.testAndSet + assert flag.testAndSet + flag.clear(moRelaxed) + assert not flag.testAndSet + +when (defined(cpp) and defined(nimUseCppAtomics)) or defined(nimdoc): # For the C++ backend, types and operations map directly to C++11 atomics. {.push, header: "<atomic>".} @@ -51,10 +91,11 @@ when defined(cpp) or defined(nimdoc): ## with other moSequentiallyConsistent operations. type - Atomic* {.importcpp: "std::atomic".} [T] = object + Atomic*[T] {.importcpp: "std::atomic", completeStruct.} = object ## An atomic object with underlying type `T`. + raw: T - AtomicFlag* {.importcpp: "std::atomic_flag".} = object + AtomicFlag* {.importcpp: "std::atomic_flag", size: 1.} = object ## An atomic boolean state. # Access operations @@ -172,8 +213,8 @@ else: # MSVC intrinsics proc interlockedExchange(location: pointer; desired: int8): int8 {.importc: "_InterlockedExchange8".} - proc interlockedExchange(location: pointer; desired: int16): int16 {.importc: "_InterlockedExchange".} - proc interlockedExchange(location: pointer; desired: int32): int32 {.importc: "_InterlockedExchange16".} + proc interlockedExchange(location: pointer; desired: int16): int16 {.importc: "_InterlockedExchange16".} + proc interlockedExchange(location: pointer; desired: int32): int32 {.importc: "_InterlockedExchange".} proc interlockedExchange(location: pointer; desired: int64): int64 {.importc: "_InterlockedExchange64".} proc interlockedCompareExchange(location: pointer; desired, expected: int8): int8 {.importc: "_InterlockedCompareExchange8".} @@ -235,10 +276,17 @@ else: cast[T](interlockedXor(addr(location.value), cast[nonAtomicType(T)](value))) else: - {.push, header: "<stdatomic.h>".} + when defined(cpp): + {.push, header: "<atomic>".} + template maybeWrapStd(x: string): string = + "std::" & x + else: + {.push, header: "<stdatomic.h>".} + template maybeWrapStd(x: string): string = + x type - MemoryOrder* {.importc: "memory_order".} = enum + MemoryOrder* {.importc: "memory_order".maybeWrapStd.} = enum moRelaxed moConsume moAcquire @@ -246,58 +294,64 @@ else: moAcquireRelease moSequentiallyConsistent - type - # Atomic* {.importcpp: "_Atomic('0)".} [T] = object + when defined(cpp): + type + # Atomic*[T] {.importcpp: "_Atomic('0)".} = object - AtomicInt8 {.importc: "_Atomic NI8".} = object - AtomicInt16 {.importc: "_Atomic NI16".} = object - AtomicInt32 {.importc: "_Atomic NI32".} = object - AtomicInt64 {.importc: "_Atomic NI64".} = object + AtomicInt8 {.importc: "std::atomic<NI8>".} = int8 + AtomicInt16 {.importc: "std::atomic<NI16>".} = int16 + AtomicInt32 {.importc: "std::atomic<NI32>".} = int32 + AtomicInt64 {.importc: "std::atomic<NI64>".} = int64 + else: + type + # Atomic*[T] {.importcpp: "_Atomic('0)".} = object - template atomicType*(T: typedesc[Trivial]): untyped = - # Maps the size of a trivial type to it's internal atomic type - when sizeof(T) == 1: AtomicInt8 - elif sizeof(T) == 2: AtomicInt16 - elif sizeof(T) == 4: AtomicInt32 - elif sizeof(T) == 8: AtomicInt64 + AtomicInt8 {.importc: "_Atomic NI8".} = int8 + AtomicInt16 {.importc: "_Atomic NI16".} = int16 + AtomicInt32 {.importc: "_Atomic NI32".} = int32 + AtomicInt64 {.importc: "_Atomic NI64".} = int64 type - AtomicFlag* {.importc: "atomic_flag".} = object + AtomicFlag* {.importc: "atomic_flag".maybeWrapStd, size: 1.} = object Atomic*[T] = object when T is Trivial: - value: T.atomicType + # Maps the size of a trivial type to it's internal atomic type + when sizeof(T) == 1: value: AtomicInt8 + elif sizeof(T) == 2: value: AtomicInt16 + elif sizeof(T) == 4: value: AtomicInt32 + elif sizeof(T) == 8: value: AtomicInt64 else: nonAtomicValue: T guard: AtomicFlag #proc init*[T](location: var Atomic[T]; value: T): T {.importcpp: "atomic_init(@)".} - proc atomic_load_explicit[T, A](location: ptr A; order: MemoryOrder): T {.importc.} - proc atomic_store_explicit[T, A](location: ptr A; desired: T; order: MemoryOrder = moSequentiallyConsistent) {.importc.} - proc atomic_exchange_explicit[T, A](location: ptr A; desired: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} - proc atomic_compare_exchange_strong_explicit[T, A](location: ptr A; expected: ptr T; desired: T; success, failure: MemoryOrder): bool {.importc.} - proc atomic_compare_exchange_weak_explicit[T, A](location: ptr A; expected: ptr T; desired: T; success, failure: MemoryOrder): bool {.importc.} + proc atomic_load_explicit[T, A](location: ptr A; order: MemoryOrder): T {.importc: "atomic_load_explicit".maybeWrapStd.} + proc atomic_store_explicit[T, A](location: ptr A; desired: T; order: MemoryOrder = moSequentiallyConsistent) {.importc: "atomic_store_explicit".maybeWrapStd.} + proc atomic_exchange_explicit[T, A](location: ptr A; desired: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_exchange_explicit".maybeWrapStd.} + proc atomic_compare_exchange_strong_explicit[T, A](location: ptr A; expected: ptr T; desired: T; success, failure: MemoryOrder): bool {.importc: "atomic_compare_exchange_strong_explicit".maybeWrapStd.} + proc atomic_compare_exchange_weak_explicit[T, A](location: ptr A; expected: ptr T; desired: T; success, failure: MemoryOrder): bool {.importc: "atomic_compare_exchange_weak_explicit".maybeWrapStd.} # Numerical operations - proc atomic_fetch_add_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} - proc atomic_fetch_sub_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} - proc atomic_fetch_and_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} - proc atomic_fetch_or_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} - proc atomic_fetch_xor_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc.} + proc atomic_fetch_add_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_fetch_add_explicit".maybeWrapStd.} + proc atomic_fetch_sub_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_fetch_sub_explicit".maybeWrapStd.} + proc atomic_fetch_and_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_fetch_and_explicit".maybeWrapStd.} + proc atomic_fetch_or_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_fetch_or_explicit".maybeWrapStd.} + proc atomic_fetch_xor_explicit[T, A](location: ptr A; value: T; order: MemoryOrder = moSequentiallyConsistent): T {.importc: "atomic_fetch_xor_explicit".maybeWrapStd.} # Flag operations # var ATOMIC_FLAG_INIT {.importc, nodecl.}: AtomicFlag # proc init*(location: var AtomicFlag) {.inline.} = location = ATOMIC_FLAG_INIT - proc testAndSet*(location: var AtomicFlag; order: MemoryOrder = moSequentiallyConsistent): bool {.importc: "atomic_flag_test_and_set_explicit".} - proc clear*(location: var AtomicFlag; order: MemoryOrder = moSequentiallyConsistent) {.importc: "atomic_flag_clear_explicit".} + proc testAndSet*(location: var AtomicFlag; order: MemoryOrder = moSequentiallyConsistent): bool {.importc: "atomic_flag_test_and_set_explicit".maybeWrapStd.} + proc clear*(location: var AtomicFlag; order: MemoryOrder = moSequentiallyConsistent) {.importc: "atomic_flag_clear_explicit".maybeWrapStd.} - proc fence*(order: MemoryOrder) {.importc: "atomic_thread_fence".} - proc signalFence*(order: MemoryOrder) {.importc: "atomic_signal_fence".} + proc fence*(order: MemoryOrder) {.importc: "atomic_thread_fence".maybeWrapStd.} + proc signalFence*(order: MemoryOrder) {.importc: "atomic_signal_fence".maybeWrapStd.} {.pop.} proc load*[T: Trivial](location: var Atomic[T]; order: MemoryOrder = moSequentiallyConsistent): T {.inline.} = - cast[T](atomic_load_explicit[nonAtomicType(T), type(location.value)](addr(location.value), order)) + cast[T](atomic_load_explicit[nonAtomicType(T), typeof(location.value)](addr(location.value), order)) proc store*[T: Trivial](location: var Atomic[T]; desired: T; order: MemoryOrder = moSequentiallyConsistent) {.inline.} = atomic_store_explicit(addr(location.value), cast[nonAtomicType(T)](desired), order) proc exchange*[T: Trivial](location: var Atomic[T]; desired: T; order: MemoryOrder = moSequentiallyConsistent): T {.inline.} = @@ -325,9 +379,11 @@ else: cast[T](atomic_fetch_xor_explicit(addr(location.value), cast[nonAtomicType(T)](value), order)) template withLock[T: not Trivial](location: var Atomic[T]; order: MemoryOrder; body: untyped): untyped = - while location.guard.testAndSet(moAcquire): discard - body - location.guard.clear(moRelease) + while testAndSet(location.guard, moAcquire): discard + try: + body + finally: + clear(location.guard, moRelease) proc load*[T: not Trivial](location: var Atomic[T]; order: MemoryOrder = moSequentiallyConsistent): T {.inline.} = withLock(location, order): @@ -345,16 +401,14 @@ else: proc compareExchange*[T: not Trivial](location: var Atomic[T]; expected: var T; desired: T; success, failure: MemoryOrder): bool {.inline.} = withLock(location, success): if location.nonAtomicValue != expected: + expected = location.nonAtomicValue return false + expected = desired swap(location.nonAtomicValue, expected) return true proc compareExchangeWeak*[T: not Trivial](location: var Atomic[T]; expected: var T; desired: T; success, failure: MemoryOrder): bool {.inline.} = - withLock(location, success): - if location.nonAtomicValue != expected: - return false - swap(location.nonAtomicValue, expected) - return true + compareExchange(location, expected, desired, success, failure) proc compareExchange*[T: not Trivial](location: var Atomic[T]; expected: var T; desired: T; order: MemoryOrder = moSequentiallyConsistent): bool {.inline.} = compareExchange(location, expected, desired, order, order) |