[compiler-rt] e40ff72 - [TSan][test-only] Make TSan os_unfair_lock.c test check the weak symbol before usage (#161173)

[via llvm-commits]

Author: Dan Blackwell
Date: 2025-10-07T16:15:00+01:00
New Revision: e40ff72df1b0e03b17e2abad40c4b97e7ae447d7

URL: https://github.com/llvm/llvm-project/commit/e40ff72df1b0e03b17e2abad40c4b97e7ae447d7
DIFF: https://github.com/llvm/llvm-project/commit/e40ff72df1b0e03b17e2abad40c4b97e7ae447d7.diff

LOG: [TSan][test-only] Make TSan os_unfair_lock.c test check the weak symbol before usage (#161173)

The os_unfair_lock.c test can currently fail with a null dereference if
compiled on a platform with `os_unfair_lock_lock_with_flags`, but then
executed on a platform without the function.

This patch fixes this by first checking whether the symbol exists, and
falls back to `os_unfair_lock_lock` if not.

rdar://160596542

Added: 
    

Modified: 
    compiler-rt/test/tsan/Darwin/os_unfair_lock.c

Removed: 
    


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diff  --git a/compiler-rt/test/tsan/Darwin/os_unfair_lock.c b/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
index e2a491aa98d6d..883154c372c7f 100644
--- a/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
+++ b/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
@@ -22,8 +22,12 @@ void *ThreadWithFlags(void *a) {
     defined(__VISIONOS_2_0) || defined(__WATCHOS_11_0)
 #  pragma clang diagnostic push
 #  pragma clang diagnostic ignored "-Wunguarded-availability-new"
-  os_unfair_lock_lock_with_flags(&lock, OS_UNFAIR_LOCK_FLAG_ADAPTIVE_SPIN);
-  flags_available = 1;
+  if (os_unfair_lock_lock_with_flags) {
+    os_unfair_lock_lock_with_flags(&lock, OS_UNFAIR_LOCK_FLAG_ADAPTIVE_SPIN);
+    flags_available = 1;
+  } else {
+    os_unfair_lock_lock(&lock);
+  }
 #  pragma clang diagnostic pop
 #else
   os_unfair_lock_lock(&lock);