[compiler-rt] [ASan][Windows] Synchronizing ASAN init on Windows (PR #71833)

[Vitaly Buka via llvm-commits]

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@@ -71,16 +71,54 @@ static void CheckUnwind() {
 }
 
 // -------------------------- Globals --------------------- {{{1
-static int asan_inited = 0;
-static int asan_init_is_running = 0;
+#if SANITIZER_WINDOWS
+atomic_uint8_t asan_inited{0};
+atomic_uint8_t asan_init_is_running{0};
+#else
+int asan_inited = 0;
+int asan_init_is_running = 0;
+#endif
 
-void SetAsanInited(u32 val) { asan_inited = val; }
+void SetAsanInited(u32 val) {
+#if SANITIZER_WINDOWS
+  atomic_store(&asan_inited, val, memory_order_release);
+#else
+  asan_inited = val;
+#endif
+}
 
-void SetAsanInitIsRunning(u32 val) { asan_init_is_running = val; }
+void SetAsanInitIsRunning(u32 val) {
+#if SANITIZER_WINDOWS
+  atomic_store(&asan_init_is_running, val, memory_order_release);
+#else
+  asan_init_is_running = val;
+#endif
+}
 
-bool AsanInited() { return asan_inited == 1; }
+bool AsanInited() {
+#if SANITIZER_WINDOWS
+  return atomic_load(&asan_inited, memory_order_acquire) == 1;
+#else
+  return asan_inited == 1;
+#endif
+}
 
-bool AsanInitIsRunning() { return asan_init_is_running == 1; }
+bool AsanInitIsRunning() {
+#if SANITIZER_WINDOWS
+  return atomic_load(&asan_init_is_running, memory_order_acquire) == 1;
+#else
+  return asan_init_is_running == 1;
+#endif
+}
+
+void CheckAsanInitRunning() {
+#if SANITIZER_WINDOWS
+  while (AsanInitIsRunning()) {
+    // If ASAN is initializing on another thread, wait for it to finish.
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vitalybuka wrote:

do we need some kind of yeld here?

https://github.com/llvm/llvm-project/pull/71833