Add annotate_ignore_thread_sanitizer_guard class

Summary:
Add `annotate_ignore_thread_sanitizer_guard` class.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D18045913

fbshipit-source-id: 39113e8df3deef3374a3c44246bc55a156bc4d8d

folly/detail/AtFork.cpp

@@ -77,15 +77,8 @@ class AtForkList {
     // so we just enable ignores for everything
     // while handling the child callbacks
     // This might still be an issue if we do not exec right away
-    annotate_ignore_reads_begin(__FILE__, __LINE__);
-    annotate_ignore_writes_begin(__FILE__, __LINE__);
-    annotate_ignore_sync_begin(__FILE__, __LINE__);
-
-    auto reenableAnnotationsGuard = folly::makeGuard([] {
-      annotate_ignore_reads_end(__FILE__, __LINE__);
-      annotate_ignore_writes_end(__FILE__, __LINE__);
-      annotate_ignore_sync_end(__FILE__, __LINE__);
-    });
+    annotate_ignore_thread_sanitizer_guard g(__FILE__, __LINE__);
+
     auto& tasks = instance().tasks;
     for (auto& task : tasks) {
       task.child();

folly/synchronization/SanitizeThread.h

@@ -189,4 +189,30 @@ FOLLY_ALWAYS_INLINE static void annotate_ignore_sync_end(const char* f, int l) {
     detail::annotate_ignore_sync_end_impl(f, l);
   }
 }
+
+class annotate_ignore_thread_sanitizer_guard {
+ public:
+  annotate_ignore_thread_sanitizer_guard(const char* file, int line)
+      : file_(file), line_(line) {
+    annotate_ignore_reads_begin(file_, line_);
+    annotate_ignore_writes_begin(file_, line_);
+    annotate_ignore_sync_begin(file_, line_);
+  }
+
+  annotate_ignore_thread_sanitizer_guard(
+      const annotate_ignore_thread_sanitizer_guard&) = delete;
+  annotate_ignore_thread_sanitizer_guard& operator=(
+      const annotate_ignore_thread_sanitizer_guard&) = delete;
+
+  ~annotate_ignore_thread_sanitizer_guard() {
+    annotate_ignore_reads_end(file_, line_);
+    annotate_ignore_writes_end(file_, line_);
+    annotate_ignore_sync_end(file_, line_);
+  }
+
+ private:
+  const char* file_;
+  int line_;
+};
+
 } // namespace folly