Split <stddef.h> out of <cstddef>.

There are a bunch of macros (__need_size_t etc) that request just one piece of
<stddef.h>; if any one of these is defined, we just directly include the
underlying header.

Note that <stddef.h> provides a ::nullptr_t. We don't want that available to
includers of <cstddef>, so instead of following the usual pattern where <cfoo>
includes <foo.h> then pulls things from :: into std:: with using-declarations,
we implement <stddef.h> and <cstddef> separately; both include <__nullptr> for
the definition of std::nullptr_t.

llvm-svn: 249761

1 files changed, 22 insertions, 0 deletions

diff --git a/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp b/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
index 140c91b53e6..c03c314e3bc 100644
--- a/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/stddef_h.pass.cpp
@@ -10,6 +10,7 @@
 // <stddef.h>
 
 #include <stddef.h>
+#include <cassert>
 #include <type_traits>
 
 #ifndef NULL
@@ -22,6 +23,9 @@
 
 int main()
 {
+    void *p = NULL;
+    assert(!p);
+
     static_assert(sizeof(size_t) == sizeof(void*),
                   "sizeof(size_t) == sizeof(void*)");
     static_assert(std::is_unsigned<size_t>::value,
@@ -34,4 +38,22 @@ int main()
                   "std::is_signed<ptrdiff_t>::value");
     static_assert(std::is_integral<ptrdiff_t>::value,
                   "std::is_integral<ptrdiff_t>::value");
+    static_assert(std::is_same<decltype(nullptr), nullptr_t>::value,
+                  "decltype(nullptr) == nullptr_t");
+    static_assert(sizeof(nullptr_t) == sizeof(void*),
+                  "sizeof(nullptr_t) == sizeof(void*)");
+    static_assert(std::is_pod<max_align_t>::value,
+                  "std::is_pod<max_align_t>::value");
+    static_assert((std::alignment_of<max_align_t>::value >=
+                  std::alignment_of<long long>::value),
+                  "std::alignment_of<max_align_t>::value >= "
+                  "std::alignment_of<long long>::value");
+    static_assert(std::alignment_of<max_align_t>::value >=
+                  std::alignment_of<long double>::value,
+                  "std::alignment_of<max_align_t>::value >= "
+                  "std::alignment_of<long double>::value");
+    static_assert(std::alignment_of<max_align_t>::value >=
+                  std::alignment_of<void*>::value,
+                  "std::alignment_of<max_align_t>::value >= "
+                  "std::alignment_of<void*>::value");
 }