| 1 | // RUN: %clang_tsan %s -o %t -undefined dynamic_lookup |
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| 2 | // RUN: %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer' |
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| 3 | |
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| 4 | #include "dispatch/dispatch.h" |
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| 5 | |
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| 6 | #include <stdio.h> |
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| 7 | |
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| 8 | // Allow compilation with pre-macOS 10.14 (and aligned) SDKs |
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| 9 | API_AVAILABLE(macos(10.14), ios(12.0), tvos(12.0), watchos(5.0)) |
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| 10 | DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW |
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| 11 | void dispatch_async_and_wait(dispatch_queue_t queue, |
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| 12 | DISPATCH_NOESCAPE dispatch_block_t block); |
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| 13 | |
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| 14 | long global; |
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| 15 | |
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| 16 | int main() { |
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| 17 | // Guard execution on pre-macOS 10.14 (and aligned) platforms |
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| 18 | if (dispatch_async_and_wait == NULL) { |
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| 19 | fprintf(stderr, format: "Done.\n" ); |
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| 20 | return 0; |
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| 21 | } |
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| 22 | |
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| 23 | dispatch_queue_t q = dispatch_queue_create("my.queue" , DISPATCH_QUEUE_SERIAL); |
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| 24 | dispatch_semaphore_t s = dispatch_semaphore_create(0); |
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| 25 | |
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| 26 | // Force queue to context switch onto separate thread. |
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| 27 | dispatch_async(q, ^{ |
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| 28 | dispatch_semaphore_wait(s, DISPATCH_TIME_FOREVER); |
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| 29 | }); |
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| 30 | dispatch_semaphore_signal(s); |
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| 31 | |
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| 32 | global++; |
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| 33 | dispatch_async_and_wait(q, ^{ |
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| 34 | // The queue continues to execute on separate thread. This would cause a |
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| 35 | // race if we had used `dispatch_async()` without the `_and_wait` part. |
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| 36 | global++; |
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| 37 | }); |
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| 38 | global++; |
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| 39 | |
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| 40 | fprintf(stderr, format: "Done.\n" ); |
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| 41 | return 0; |
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| 42 | } |
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| 43 | |
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| 44 | // CHECK: Done. |
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| 45 | |
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