1 files changed, 95 insertions, 0 deletions
diff --git a/lib/scudo/scudo_tls_android.cpp b/lib/scudo/scudo_tls_android.cpp
new file mode 100644
index 0000000000000..0e3602b2faf01
--- /dev/null
+++ b/lib/scudo/scudo_tls_android.cpp
@@ -0,0 +1,95 @@
+//===-- scudo_tls_android.cpp -----------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// Scudo thread local structure implementation for Android.
+///
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+
+#if SANITIZER_LINUX && SANITIZER_ANDROID
+
+#include "scudo_tls.h"
+
+#include <pthread.h>
+
+namespace __scudo {
+
+static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
+static pthread_key_t PThreadKey;
+
+static atomic_uint32_t ThreadContextCurrentIndex;
+static ScudoThreadContext *ThreadContexts;
+static uptr NumberOfContexts;
+
+// sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used as they allocate memory.
+static uptr getNumberOfCPUs() {
+  cpu_set_t CPUs;
+  CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
+  return CPU_COUNT(&CPUs);
+}
+
+static void initOnce() {
+  // Hack: TLS_SLOT_TSAN was introduced in N. To be able to use it on M for
+  // testing, we create an unused key. Since the key_data array follows the tls
+  // array, it basically gives us the extra entry we need.
+  // TODO(kostyak): remove and restrict to N and above.
+  CHECK_EQ(pthread_key_create(&PThreadKey, NULL), 0);
+  initScudo();
+  NumberOfContexts = getNumberOfCPUs();
+  ThreadContexts = reinterpret_cast<ScudoThreadContext *>(
+      MmapOrDie(sizeof(ScudoThreadContext) * NumberOfContexts, __func__));
+  for (int i = 0; i < NumberOfContexts; i++)
+    ThreadContexts[i].init();
+}
+
+void initThread() {
+  pthread_once(&GlobalInitialized, initOnce);
+  // Initial context assignment is done in a plain round-robin fashion.
+  u32 Index = atomic_fetch_add(&ThreadContextCurrentIndex, 1,
+                               memory_order_relaxed);
+  ScudoThreadContext *ThreadContext =
+      &ThreadContexts[Index % NumberOfContexts];
+  *get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
+}
+
+ScudoThreadContext *getThreadContextAndLockSlow() {
+  ScudoThreadContext *ThreadContext;
+  // Go through all the contexts and find the first unlocked one. 
+  for (u32 i = 0; i < NumberOfContexts; i++) {
+    ThreadContext = &ThreadContexts[i];
+    if (ThreadContext->tryLock()) {
+      *get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
+      return ThreadContext;
+    }
+  }
+  // No luck, find the one with the lowest precedence, and slow lock it.
+  u64 Precedence = UINT64_MAX;
+  for (u32 i = 0; i < NumberOfContexts; i++) {
+    u64 SlowLockPrecedence = ThreadContexts[i].getSlowLockPrecedence();
+    if (SlowLockPrecedence && SlowLockPrecedence < Precedence) {
+      ThreadContext = &ThreadContexts[i];
+      Precedence = SlowLockPrecedence;
+    }
+  }
+  if (LIKELY(Precedence != UINT64_MAX)) {
+    ThreadContext->lock();
+    *get_android_tls_ptr() = reinterpret_cast<uptr>(ThreadContext);
+    return ThreadContext;
+  }
+  // Last resort (can this happen?), stick with the current one.
+  ThreadContext =
+      reinterpret_cast<ScudoThreadContext *>(*get_android_tls_ptr());
+  ThreadContext->lock();
+  return ThreadContext;
+}
+
+}  // namespace __scudo
+
+#endif  // SANITIZER_LINUX && SANITIZER_ANDROID