1 files changed, 96 insertions, 0 deletions
diff --git a/compiler-rt/lib/scudo/scudo_tsd_shared.cpp b/compiler-rt/lib/scudo/scudo_tsd_shared.cpp
new file mode 100644
index 00000000000..481635e6a59
--- /dev/null
+++ b/compiler-rt/lib/scudo/scudo_tsd_shared.cpp
@@ -0,0 +1,96 @@
+//===-- scudo_tsd_shared.cpp ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// Scudo shared TSD implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "scudo_tsd.h"
+
+#if !SCUDO_TSD_EXCLUSIVE
+
+#include <pthread.h>
+
+namespace __scudo {
+
+static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
+static pthread_key_t PThreadKey;
+
+static atomic_uint32_t CurrentIndex;
+static ScudoTSD *TSDs;
+static u32 NumberOfTSDs;
+
+// 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();
+  NumberOfTSDs = getNumberOfCPUs();
+  if (NumberOfTSDs == 0)
+    NumberOfTSDs = 1;
+  if (NumberOfTSDs > 32)
+    NumberOfTSDs = 32;
+  TSDs = reinterpret_cast<ScudoTSD *>(
+      MmapOrDie(sizeof(ScudoTSD) * NumberOfTSDs, "ScudoTSDs"));
+  for (u32 i = 0; i < NumberOfTSDs; i++)
+    TSDs[i].init(/*Shared=*/true);
+}
+
+void initThread(bool MinimalInit) {
+  pthread_once(&GlobalInitialized, initOnce);
+  // Initial context assignment is done in a plain round-robin fashion.
+  u32 Index = atomic_fetch_add(&CurrentIndex, 1, memory_order_relaxed);
+  ScudoTSD *TSD = &TSDs[Index % NumberOfTSDs];
+  *get_android_tls_ptr() = reinterpret_cast<uptr>(TSD);
+}
+
+ScudoTSD *getTSDAndLockSlow() {
+  ScudoTSD *TSD;
+  if (NumberOfTSDs > 1) {
+    // Go through all the contexts and find the first unlocked one.
+    for (u32 i = 0; i < NumberOfTSDs; i++) {
+      TSD = &TSDs[i];
+      if (TSD->tryLock()) {
+        *get_android_tls_ptr() = reinterpret_cast<uptr>(TSD);
+        return TSD;
+      }
+    }
+    // No luck, find the one with the lowest Precedence, and slow lock it.
+    u64 LowestPrecedence = UINT64_MAX;
+    for (u32 i = 0; i < NumberOfTSDs; i++) {
+      u64 Precedence = TSDs[i].getPrecedence();
+      if (Precedence && Precedence < LowestPrecedence) {
+        TSD = &TSDs[i];
+        LowestPrecedence = Precedence;
+      }
+    }
+    if (LIKELY(LowestPrecedence != UINT64_MAX)) {
+      TSD->lock();
+      *get_android_tls_ptr() = reinterpret_cast<uptr>(TSD);
+      return TSD;
+    }
+  }
+  // Last resort, stick with the current one.
+  TSD = reinterpret_cast<ScudoTSD *>(*get_android_tls_ptr());
+  TSD->lock();
+  return TSD;
+}
+
+}  // namespace __scudo
+
+#endif  // !SCUDO_TSD_EXCLUSIVE