[PATCH] D55596: Reimplement Thread Static Data ASan routines with TLS

[Kamil Rytarowski via Phabricator via llvm-commits]

krytarowski updated this revision to Diff 178646.
krytarowski retitled this revision from "Reimplement Thread Static Data ASan routines for NetBSD" to "Reimplement Thread Static Data ASan routines with TLS".
krytarowski edited the summary of this revision.
krytarowski added a comment.
Herald added a subscriber: emaste.

- add new implementation
- include FreeBSD


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55596/new/

https://reviews.llvm.org/D55596

Files:
  lib/asan/asan_posix.cc


Index: lib/asan/asan_posix.cc
===================================================================
--- lib/asan/asan_posix.cc
+++ lib/asan/asan_posix.cc
@@ -40,6 +40,53 @@
 
 // ---------------------- TSD ---------------- {{{1
 
+#if SANITIZER_NETBSD || SANITIZER_FREEBSD
+// Thread Static Data cannot be used in early init on NetBSD
+// Reuse the Asan TSD API for compatibility with existing code
+// with an alternative implementation.
+
+static bool tsd_key_inited = false;
+static void (*tsd_destructor)(void *tsd) = nullptr;
+
+struct tsd_key {
+  tsd_key() : key(nullptr) {}
+  ~tsd_key() {
+    CHECK(tsd_destructor);
+    if (key)
+      (*tsd_destructor)(key);
+  }
+  void *key;
+};
+
+static thread_local struct tsd_key key;
+
+void AsanTSDInit(void (*destructor)(void *tsd)) {
+  CHECK(!tsd_key_inited);
+  tsd_key_inited = true;
+  tsd_destructor = destructor;
+}
+
+void *AsanTSDGet() {
+  CHECK(tsd_key_inited);
+  return key.key;
+}
+
+void AsanTSDSet(void *tsd) {
+  CHECK(tsd_key_inited);
+  CHECK(tsd);
+  CHECK(!key.key);
+  key.key = tsd;
+}
+
+void PlatformTSDDtor(void *tsd) {
+  CHECK(tsd_key_inited);
+  CHECK(key.key);
+  key.key = nullptr;
+  // Make sure that signal handler can not see a stale current thread pointer.
+  atomic_signal_fence(memory_order_seq_cst);
+  AsanThread::TSDDtor(tsd);
+}
+#else
 static pthread_key_t tsd_key;
 static bool tsd_key_inited = false;
 void AsanTSDInit(void (*destructor)(void *tsd)) {
@@ -67,6 +114,7 @@
   }
   AsanThread::TSDDtor(tsd);
 }
+#endif
 }  // namespace __asan
 
 #endif  // SANITIZER_POSIX


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