[PATCH] D55703: Reimplement Thread Static Data MSan routines with TLS

[Kamil Rytarowski via Phabricator via llvm-commits]

krytarowski updated this revision to Diff 178861.
krytarowski retitled this revision from "Reimplement Thread Static Data MSan routines for NetBSD" to "Reimplement Thread Static Data MSan routines with TLS".
krytarowski edited the summary of this revision.
Herald added a subscriber: emaste.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55703/new/

https://reviews.llvm.org/D55703

Files:
  lib/msan/msan_linux.cc


Index: lib/msan/msan_linux.cc
===================================================================
--- lib/msan/msan_linux.cc
+++ lib/msan/msan_linux.cc
@@ -175,6 +175,51 @@
 
 // ---------------------- TSD ---------------- {{{1
 
+#if SANITIZER_NETBSD || SANITIZER_FREEBSD
+// Thread Static Data cannot be used in early init on NetBSD and FreeBSD.
+// Reuse the MSan TSD API for compatibility with existing code
+// with an alternative implementation.
+
+static void (*tsd_destructor)(void *tsd) = nullptr;
+
+struct tsd_key {
+  tsd_key() : key(nullptr) {}
+  ~tsd_key() {
+    CHECK(tsd_destructor);
+    if (key)
+      (*tsd_destructor)(key);
+  }
+  MsanThread *key;
+};
+
+static thread_local struct tsd_key key;
+
+void MsanTSDInit(void (*destructor)(void *tsd)) {
+  CHECK(!tsd_destructor);
+  tsd_destructor = destructor;
+}
+
+MsanThread *GetCurrentThread() {
+  CHECK(tsd_destructor);
+  return key.key;
+}
+
+void SetCurrentThread(MsanThread *tsd) {
+  CHECK(tsd_destructor);
+  CHECK(tsd);
+  CHECK(!key.key);
+  key.key = tsd;
+}
+
+void MsanTSDDtor(void *tsd) {
+  CHECK(tsd_destructor);
+  CHECK_EQ(key.key, tsd);
+  key.key = nullptr;
+  // Make sure that signal handler can not see a stale current thread pointer.
+  atomic_signal_fence(memory_order_seq_cst);
+  MsanThread::TSDDtor(tsd);
+}
+#else
 static pthread_key_t tsd_key;
 static bool tsd_key_inited = false;
 
@@ -211,6 +256,7 @@
   atomic_signal_fence(memory_order_seq_cst);
   MsanThread::TSDDtor(tsd);
 }
+#endif
 
 } // namespace __msan
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D55703.178861.patch
Type: text/x-patch
Size: 1520 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20181219/175e1db4/attachment.bin>