[scudo] Allow for non-Android Shared TSD platforms, part 2

Summary:
Follow up to D38826.

We introduce `pthread_{get,set}specific` versions of `{get,set}CurrentTSD` to
allow for non Android platforms to use the Shared TSD model.
We now allow `SCUDO_TSD_EXCLUSIVE` to be defined at compile time.

A couple of things:
- I know that `#if SANITIZER_ANDROID` is not ideal within a function, but in
  the end I feel it looks more compact and clean than going the .inc route; I
  am open to an alternative if anyone has one;
- `SCUDO_TSD_EXCLUSIVE=1` requires ELF TLS support (and not emutls as this uses
  malloc). I haven't found anything to enforce that, so it's currently not
  checked.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D38854

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@315751 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 5 deletions

diff --git a/lib/scudo/scudo_tsd_shared.cpp b/lib/scudo/scudo_tsd_shared.cpp
index 54aec842a..6ee2f84a0 100644
--- a/lib/scudo/scudo_tsd_shared.cpp
+++ b/lib/scudo/scudo_tsd_shared.cpp
@@ -18,7 +18,7 @@
 namespace __scudo {
 
 static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
-static pthread_key_t PThreadKey;
+pthread_key_t PThreadKey;
 
 static atomic_uint32_t CurrentIndex;
 static ScudoTSD *TSDs;
@@ -32,10 +32,6 @@ static uptr getNumberOfCPUs() {
 }
 
 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();
@@ -50,7 +46,11 @@ static void initOnce() {
 }
 
 ALWAYS_INLINE void setCurrentTSD(ScudoTSD *TSD) {
+#if SANITIZER_ANDROID
   *get_android_tls_ptr() = reinterpret_cast<uptr>(TSD);
+#else
+  CHECK_EQ(pthread_setspecific(PThreadKey, reinterpret_cast<void *>(TSD)), 0);
+#endif  // SANITIZER_ANDROID
 }
 
 void initThread(bool MinimalInit) {