Implement `internal_start/join_thread` on Mac OS X

Summary: Depends on D9637

Test Plan:

Reviewers: kcc, glider, samsonov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9638

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@252696 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/sanitizer_common/sanitizer_mac.cc b/lib/sanitizer_common/sanitizer_mac.cc
index 3151cf8b9..03e97c84e 100644
--- a/lib/sanitizer_common/sanitizer_mac.cc
+++ b/lib/sanitizer_common/sanitizer_mac.cc
@@ -371,8 +371,18 @@ uptr GetRSS() {
   return info.resident_size;
 }
 
-void *internal_start_thread(void (*func)(void *arg), void *arg) { return 0; }
-void internal_join_thread(void *th) { }
+void *internal_start_thread(void(*func)(void *arg), void *arg) {
+  // Start the thread with signals blocked, otherwise it can steal user signals.
+  __sanitizer_sigset_t set, old;
+  internal_sigfillset(&set);
+  internal_sigprocmask(SIG_SETMASK, &set, &old);
+  pthread_t th;
+  pthread_create(&th, 0, (void*(*)(void *arg))func, arg);
+  internal_sigprocmask(SIG_SETMASK, &old, 0);
+  return th;
+}
+
+void internal_join_thread(void *th) { pthread_join((pthread_t)th, 0); }
 
 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
   ucontext_t *ucontext = (ucontext_t*)context;