[compiler-rt] [TSan] Add interceptor for os_unfair_lock_lock_with_flags (PR #153815)

[Dan Blackwell via llvm-commits]

https://github.com/DanBlackwell updated https://github.com/llvm/llvm-project/pull/153815

>From b13c3ed2cf1f73fec4f7fbdfa1bdd57594d109ef Mon Sep 17 00:00:00 2001
From: Dan Blackwell <dan_blackwell at apple.com>
Date: Fri, 15 Aug 2025 11:55:16 +0100
Subject: [PATCH] [TSan] Add interceptor for os_unfair_lock_lock_with_flags

Also update os_unfair_lock tsan test to check this function on platforms where it is available.
---
 .../lib/tsan/rtl/tsan_interceptors_mac.cpp    | 19 ++++++++++++
 compiler-rt/test/tsan/Darwin/os_unfair_lock.c | 30 ++++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_mac.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_mac.cpp
index 978664411fff4..c5e12b472aacc 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_mac.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_mac.cpp
@@ -281,6 +281,25 @@ TSAN_INTERCEPTOR(void, os_unfair_lock_lock, os_unfair_lock_t lock) {
   Acquire(thr, pc, (uptr)lock);
 }
 
+// os_unfair_lock_lock_with_flags was introduced in macOS 15
+#  if defined(__MAC_15_0) || defined(__IPHONE_18_0) || defined(__TVOS_18_0) || \
+      defined(__VISIONOS_2_0) || defined(__WATCHOS_11_0)
+#    pragma clang diagnostic push
+#    pragma clang diagnostic ignored "-Wunguarded-availability-new"
+// We're just intercepting this - if it doesn't exist on the platform, then the
+// process shouldn't have called it in the first place.
+TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_flags, os_unfair_lock_t lock,
+                 os_unfair_lock_flags_t flags) {
+  if (!cur_thread()->is_inited || cur_thread()->is_dead) {
+    return REAL(os_unfair_lock_lock_with_flags)(lock, flags);
+  }
+  SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock_with_flags, lock, flags);
+  REAL(os_unfair_lock_lock_with_flags)(lock, flags);
+  Acquire(thr, pc, (uptr)lock);
+}
+#    pragma clang diagnostic pop
+#  endif
+
 TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_options, os_unfair_lock_t lock,
                  u32 options) {
   if (!cur_thread()->is_inited || cur_thread()->is_dead) {
diff --git a/compiler-rt/test/tsan/Darwin/os_unfair_lock.c b/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
index 320e7f5e56d1d..e2a491aa98d6d 100644
--- a/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
+++ b/compiler-rt/test/tsan/Darwin/os_unfair_lock.c
@@ -1,12 +1,14 @@
 // RUN: %clang_tsan %s -o %t
 // RUN: %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer'
 
+#include <Availability.h>
 #include <os/lock.h>
 #include <pthread.h>
 #include <stdio.h>
 
 long global_variable;
 os_unfair_lock lock = OS_UNFAIR_LOCK_INIT;
+char flags_available = 0;
 
 void *Thread(void *a) {
   os_unfair_lock_lock(&lock);
@@ -15,6 +17,22 @@ void *Thread(void *a) {
   return NULL;
 }
 
+void *ThreadWithFlags(void *a) {
+#if defined(__MAC_15_0) || defined(__IPHONE_18_0) || defined(__TVOS_18_0) ||   \
+    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;
+#  pragma clang diagnostic pop
+#else
+  os_unfair_lock_lock(&lock);
+#endif
+  global_variable++;
+  os_unfair_lock_unlock(&lock);
+  return NULL;
+}
+
 int main() {
   pthread_t t1, t2;
   global_variable = 0;
@@ -23,6 +41,16 @@ int main() {
   pthread_join(t1, NULL);
   pthread_join(t2, NULL);
   fprintf(stderr, "global_variable = %ld\n", global_variable);
+
+  // CHECK: global_variable = 2
+
+  pthread_create(&t1, NULL, ThreadWithFlags, NULL);
+  pthread_create(&t2, NULL, ThreadWithFlags, NULL);
+  pthread_join(t1, NULL);
+  pthread_join(t2, NULL);
+  fprintf(stderr,
+          "global_variable = %ld, os_unfair_lock_lock_with_flags %savailable\n",
+          global_variable, flags_available ? "" : "un");
 }
 
-// CHECK: global_variable = 2
+// CHECK: global_variable = 4