commit 03776e74b31d0bf031e7508d4aba1181713651fa
author Nico Weber <nicolasweber@gmx.de> Wed Mar 20 22:55:03 2019 +0000
committer Nico Weber <nicolasweber@gmx.de> Wed Mar 20 22:55:03 2019 +0000
tree e2ad3a1c6faebf8aa7d1477e96026802acf2e90f
parent f6bf76a1bd6bb06a0230167f8b1b781e558bbc54

libc++/win: Make once_flag have the same size as a pointer.

`unsigned long` is 32-bit on 32-bit systems and 64-bit on 64-bit systems
on LP64 systems -- which most Unix systems are, but Windows isn't.
Windows is LLP64, which means unsigned long is 32-bit even on 64-bit
systems.

pplwin.h contains

    static_assert(alignof(void *) == alignof(::std::once_flag), ...)

which fails due to this problem.

Instead of unsigned long, use uintptr_t, which consistently is 32-bit
on 32-bit systems and 64-bit on 64-bit systems.

No functional change except on 64-bit Windows.

Differential Revision: https://reviews.llvm.org/D59607

llvm-svn: 356624
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 0fd00a581d929c3caa2e92fbd06cdc1ae88fa457

include/mutex

diff --git a/include/mutex b/include/mutex
index 98bd581..20c3ffc 100644
--- a/include/mutex
+++ b/include/mutex
@@ -188,6 +188,7 @@
 
 #include <__config>
 #include <__mutex_base>
+#include <cstdint>
 #include <functional>
 #include <memory>
 #ifndef _LIBCPP_CXX03_LANG
@@ -575,11 +576,18 @@
     _LIBCPP_CONSTEXPR
         once_flag() _NOEXCEPT : __state_(0) {}
 
+#if defined(_LIBCPP_ABI_MICROSOFT)
+   typedef uintptr_t _State_type;
+#else
+   typedef unsigned long _State_type;
+#endif
+
+
 private:
     once_flag(const once_flag&); // = delete;
     once_flag& operator=(const once_flag&); // = delete;
 
-    unsigned long __state_;
+    _State_type __state_;
 
 #ifndef _LIBCPP_CXX03_LANG
     template<class _Callable, class... _Args>
@@ -649,7 +657,8 @@
     (*__p)();
 }
 
-_LIBCPP_FUNC_VIS void __call_once(volatile unsigned long&, void*, void(*)(void*));
+_LIBCPP_FUNC_VIS void __call_once(volatile once_flag::_State_type&, void*,
+                                  void (*)(void*));
 
 #ifndef _LIBCPP_CXX03_LANG
 
@@ -658,7 +667,7 @@
 void
 call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
 {
-    if (__libcpp_acquire_load(&__flag.__state_) != ~0ul)
+    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
     {
         typedef tuple<_Callable&&, _Args&&...> _Gp;
         _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
@@ -674,7 +683,7 @@
 void
 call_once(once_flag& __flag, _Callable& __func)
 {
-    if (__libcpp_acquire_load(&__flag.__state_) != ~0ul)
+    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
     {
         __call_once_param<_Callable> __p(__func);
         __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
@@ -686,7 +695,7 @@
 void
 call_once(once_flag& __flag, const _Callable& __func)
 {
-    if (__libcpp_acquire_load(&__flag.__state_) != ~0ul)
+    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
     {
         __call_once_param<const _Callable> __p(__func);
         __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);