[sanitizer] Use pthread_threadid_np as thread ID on OS X

Let's use pthread_threadid_np which returns a more reasonable ID than pthread_self (which is actually a stack pointer). The numbers from pthread_threadid_np are already used in other tools, e.g. in LLDB, and often appear in logs, so it's much more useful than pthread_self.

Differential Revision: http://reviews.llvm.org/D18951

llvm-svn: 266991

1 files changed, 4 insertions, 1 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
index c2e8b1ec38f..5fbb147297c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
@@ -230,7 +230,10 @@ bool FileExists(const char *filename) {
 }
 
 uptr GetTid() {
-  return reinterpret_cast<uptr>(pthread_self());
+  // FIXME: This can potentially get truncated on 32-bit, where uptr is 4 bytes.
+  uint64_t tid;
+  pthread_threadid_np(nullptr, &tid);
+  return tid;
 }
 
 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,