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Fix memory leaks in ThreadBarriers.swift #12212

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Merged
merged 5 commits into from
Jan 29, 2020
Merged

Fix memory leaks in ThreadBarriers.swift #12212

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38377df
Fix memory leaks in ThreadBarriers.swift
Dec 4, 2019
315f510
Fatal error on pthread cond/mutex destroy failure
Dec 4, 2019
9e80f27
Rename pthread to thread
Dec 9, 2019
f0e31ee
Fix pthread init function calls
Dec 10, 2019
c1e6cf8
Fix guard statement
Dec 11, 2019
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5 changes: 1 addition & 4 deletions stdlib/private/SwiftPrivateThreadExtras/SwiftPrivateThreadExtras.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -162,10 +162,7 @@ public class _stdlib_Barrier {
}

deinit {
let ret = _stdlib_thread_barrier_destroy(_threadBarrierPtr)
if ret != 0 {
fatalError("_stdlib_thread_barrier_destroy() failed")
}
_stdlib_thread_barrier_destroy(_threadBarrierPtr)
}

public func wait() {
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36 changes: 21 additions & 15 deletions stdlib/private/SwiftPrivateThreadExtras/ThreadBarriers.swift
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Expand Up @@ -69,34 +69,40 @@ public func _stdlib_thread_barrier_init(
InitializeConditionVariable(barrier.pointee.cond!)
#else
barrier.pointee.mutex = UnsafeMutablePointer.allocate(capacity: 1)
if pthread_mutex_init(barrier.pointee.mutex!, nil) != 0 {
// FIXME: leaking memory.
return -1
}
barrier.pointee.cond = UnsafeMutablePointer.allocate(capacity: 1)
if pthread_cond_init(barrier.pointee.cond!, nil) != 0 {
// FIXME: leaking memory, leaking a mutex.
guard _stdlib_thread_barrier_mutex_and_cond_init(barrier) == 0 else {
barrier.pointee.mutex!.deinitialize(count: 1)
barrier.pointee.mutex!.deallocate()
barrier.pointee.cond!.deinitialize(count: 1)
barrier.pointee.cond!.deallocate()
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This has to exit the enclosing scope.

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Thanks! Rebasing isn't as straightforward as I thought, I'll try building locally this time

return -1
}
#endif
barrier.pointee.count = count
return 0
}

private func _stdlib_thread_barrier_mutex_and_cond_init(_ barrier: UnsafeMutablePointer<_stdlib_thread_barrier_t>) -> CInt {
guard pthread_mutex_init(barrier.pointee.mutex!, nil) == 0 else {
return -1
}
guard pthread_cond_init(barrier.pointee.cond!, nil) == 0 else {
pthread_mutex_destroy(barrier.pointee.mutex!)
return -1
}
return 0
}

public func _stdlib_thread_barrier_destroy(
_ barrier: UnsafeMutablePointer<_stdlib_thread_barrier_t>
) -> CInt {
) {
#if os(Windows)
// Condition Variables do not need to be explicitly destroyed
// Mutexes do not need to be explicitly destroyed
#else
if pthread_cond_destroy(barrier.pointee.cond!) != 0 {
// FIXME: leaking memory, leaking a mutex.
return -1
}
if pthread_mutex_destroy(barrier.pointee.mutex!) != 0 {
// FIXME: leaking memory.
return -1
guard pthread_cond_destroy(barrier.pointee.cond!) == 0 &&
pthread_mutex_destroy(barrier.pointee.mutex!) == 0 else {
fatalError("_stdlib_thread_barrier_destroy() failed")
}
#endif
barrier.pointee.cond!.deinitialize(count: 1)
Expand All @@ -105,7 +111,7 @@ public func _stdlib_thread_barrier_destroy(
barrier.pointee.mutex!.deinitialize(count: 1)
barrier.pointee.mutex!.deallocate()

return 0
return
}

public func _stdlib_thread_barrier_wait(
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3 changes: 1 addition & 2 deletions validation-test/stdlib/StringSlicesConcurrentAppend.swift
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Expand Up @@ -111,8 +111,7 @@ StringTestSuite.test("SliceConcurrentAppend") {
expectEqual(0, joinRet1)
expectEqual(0, joinRet2)

ret = _stdlib_thread_barrier_destroy(barrierVar!)
expectEqual(0, ret)
_stdlib_thread_barrier_destroy(barrierVar!)

barrierVar!.deinitialize(count: 1)
barrierVar!.deallocate()
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