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25c94eb152
We incorrectly replaced shadow slots when the new value is not stronger than the old one. The bug can lead to false negatives. The bug was detected by Go race test suite: https://github.com/golang/go/issues/10589 llvm-svn: 236008
41 lines
1010 B
C
41 lines
1010 B
C
// RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
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#include "test.h"
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// We want to establish the following sequence of accesses to X:
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// - main thread writes X
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// - thread2 reads X, this read happens-before the write in main thread
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// - thread1 reads X, this read is concurrent with the write in main thread
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// Write in main thread and read in thread1 should be detected as a race.
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// Previously tsan replaced write by main thread with read by thread1,
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// as the result the race was not detected.
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volatile long X, Y, Z;
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void *Thread1(void *x) {
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barrier_wait(&barrier);
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barrier_wait(&barrier);
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Y = X;
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return NULL;
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}
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void *Thread2(void *x) {
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Z = X;
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barrier_wait(&barrier);
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return NULL;
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}
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int main() {
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barrier_init(&barrier, 2);
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pthread_t t[2];
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pthread_create(&t[0], 0, Thread1, 0);
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X = 42;
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barrier_wait(&barrier);
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pthread_create(&t[1], 0, Thread2, 0);
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pthread_join(t[0], 0);
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pthread_join(t[1], 0);
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return 0;
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}
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// CHECK: WARNING: ThreadSanitizer: data race
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