[libcxx-commits] [libcxx] e6c89a4 - [SystemZ][ZOS] Fix the usage of pthread_t within libc++

[Zbigniew Sarbinowski via libcxx-commits]

Author: Zbigniew Sarbinowski
Date: 2020-12-05T17:46:30Z
New Revision: e6c89a499d91b5d50ac556428dac995d07f0f6e5

URL: https://github.com/llvm/llvm-project/commit/e6c89a499d91b5d50ac556428dac995d07f0f6e5
DIFF: https://github.com/llvm/llvm-project/commit/e6c89a499d91b5d50ac556428dac995d07f0f6e5.diff

LOG: [SystemZ][ZOS] Fix the usage of pthread_t within libc++

This is the the minimal change introduced in [[ https://reviews.llvm.org/D88599 | D88599 ]]  to unblock the controversial change and discussion of proper separation between thread from thread id which will continue in D88599.

This patch will address the differences of definition of pthread_t on z/OS vs. Linux and other OS. Main trick to make the code work on z/OS relies on redefining libcpp_thread_id type and _LIBCPP_NULL_THREAD macro. This is necessary to separate initialization of libcxx_thread_id from the one of __libcxx_thread_t;

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D91875

Added: 
    

Modified: 
    libcxx/include/__config
    libcxx/include/__threading_support

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__config b/libcxx/include/__config
index 3f56a022177d..d2fdf6785c7e 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1113,6 +1113,7 @@ _LIBCPP_FUNC_VIS extern "C" void __sanitizer_annotate_contiguous_container(
       defined(__APPLE__) || \
       defined(__CloudABI__) || \
       defined(__sun__) || \
+      defined(__MVS__) || \
       (defined(__MINGW32__) && __has_include(<pthread.h>))
 #    define _LIBCPP_HAS_THREAD_API_PTHREAD
 #  elif defined(__Fuchsia__)

diff  --git a/libcxx/include/__threading_support b/libcxx/include/__threading_support
index 2d0ccf5cb244..473c9c3bbe49 100644
--- a/libcxx/include/__threading_support
+++ b/libcxx/include/__threading_support
@@ -31,7 +31,7 @@
 #if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
 # include <pthread.h>
 # include <sched.h>
-# ifdef __APPLE__
+# if defined(__APPLE__) || defined(__MVS__)
 #  define _LIBCPP_NO_NATIVE_SEMAPHORES
 # endif
 # ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
@@ -87,11 +87,14 @@ typedef pthread_once_t __libcpp_exec_once_flag;
 #define _LIBCPP_EXEC_ONCE_INITIALIZER PTHREAD_ONCE_INIT
 
 // Thread id
-typedef pthread_t __libcpp_thread_id;
+#if defined(__MVS__)
+  typedef unsigned long long __libcpp_thread_id;
+#else
+  typedef pthread_t __libcpp_thread_id;
+#endif
 
 // Thread
-#define _LIBCPP_NULL_THREAD 0U
-
+#define _LIBCPP_NULL_THREAD ((__libcpp_thread_t()))
 typedef pthread_t __libcpp_thread_t;
 
 // Thread Local Storage
@@ -486,7 +489,7 @@ int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
 // Returns non-zero if the thread ids are equal, otherwise 0
 bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2)
 {
-  return pthread_equal(t1, t2) != 0;
+  return t1 == t2;
 }
 
 // Returns non-zero if t1 < t2, otherwise 0
@@ -508,12 +511,17 @@ int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
 
 __libcpp_thread_id __libcpp_thread_get_current_id()
 {
-  return pthread_self();
+  const __libcpp_thread_t thread = pthread_self();
+  return __libcpp_thread_get_id(&thread);
 }
 
 __libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
 {
+#if defined(__MVS__)
+  return __t->__;
+#else
   return *__t;
+#endif
 }
 
 int __libcpp_thread_join(__libcpp_thread_t *__t)
@@ -653,7 +661,7 @@ bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2)
 
 // Thread
 bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
-  return *__t == 0;
+  return __libcpp_thread_get_id(__t) == 0;
 }
 
 int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),