From cdf4f3055e964bb585f294cf77cb549ead82783f Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Mon, 18 Dec 2017 20:11:54 +0000
Subject: Vendor import of compiler-rt trunk r321017:
 https://llvm.org/svn/llvm-project/compiler-rt/trunk@321017

---
 lib/scudo/scudo_tsd_exclusive.cpp | 68 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 lib/scudo/scudo_tsd_exclusive.cpp

(limited to 'lib/scudo/scudo_tsd_exclusive.cpp')

diff --git a/lib/scudo/scudo_tsd_exclusive.cpp b/lib/scudo/scudo_tsd_exclusive.cpp
new file mode 100644
index 000000000000..1084dfac91e1
--- /dev/null
+++ b/lib/scudo/scudo_tsd_exclusive.cpp
@@ -0,0 +1,68 @@
+//===-- scudo_tsd_exclusive.cpp ---------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// Scudo exclusive TSD implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "scudo_tsd.h"
+
+#if SCUDO_TSD_EXCLUSIVE
+
+namespace __scudo {
+
+static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
+static pthread_key_t PThreadKey;
+
+__attribute__((tls_model("initial-exec")))
+THREADLOCAL ThreadState ScudoThreadState = ThreadNotInitialized;
+__attribute__((tls_model("initial-exec")))
+THREADLOCAL ScudoTSD TSD;
+
+// Fallback TSD for when the thread isn't initialized yet or is torn down. It
+// can be shared between multiple threads and as such must be locked.
+ScudoTSD FallbackTSD;
+
+static void teardownThread(void *Ptr) {
+  uptr I = reinterpret_cast<uptr>(Ptr);
+  // The glibc POSIX thread-local-storage deallocation routine calls user
+  // provided destructors in a loop of PTHREAD_DESTRUCTOR_ITERATIONS.
+  // We want to be called last since other destructors might call free and the
+  // like, so we wait until PTHREAD_DESTRUCTOR_ITERATIONS before draining the
+  // quarantine and swallowing the cache.
+  if (I > 1) {
+    // If pthread_setspecific fails, we will go ahead with the teardown.
+    if (LIKELY(pthread_setspecific(PThreadKey,
+                                   reinterpret_cast<void *>(I - 1)) == 0))
+      return;
+  }
+  TSD.commitBack();
+  ScudoThreadState = ThreadTornDown;
+}
+
+
+static void initOnce() {
+  CHECK_EQ(pthread_key_create(&PThreadKey, teardownThread), 0);
+  initScudo();
+  FallbackTSD.init(/*Shared=*/true);
+}
+
+void initThread(bool MinimalInit) {
+  CHECK_EQ(pthread_once(&GlobalInitialized, initOnce), 0);
+  if (UNLIKELY(MinimalInit))
+    return;
+  CHECK_EQ(pthread_setspecific(PThreadKey, reinterpret_cast<void *>(
+      GetPthreadDestructorIterations())), 0);
+  TSD.init(/*Shared=*/false);
+  ScudoThreadState = ThreadInitialized;
+}
+
+}  // namespace __scudo
+
+#endif  // SCUDO_TSD_EXCLUSIVE
-- 
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