For KMP_PAGE_SIZE, use getpagesize() on Unix, GetSystemInfo() on Windows

Summary:
The kmp_os.h header is defining the `PAGE_SIZE` macro unconditionally,
even while it is only used directly after its definition, for the
Windows implementation of the `KMP_GET_PAGE_SIZE()` macro.

On at least FreeBSD, but likely all other BSDs too, this macro conflicts
with the one defined in system headers, so remove it, since nothing else
uses it.  Make all Unixes use `getpagesize()` instead, and use
`GetSystemInfo()` for the Windows case.

Reviewers: jlpeyton, jcownie, emaste, AndreyChurbanov

Reviewed By: AndreyChurbanov

Subscribers: AndreyChurbanov, hfinkel, zturner

Differential Revision: https://reviews.llvm.org/D35072


git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@308355 91177308-0d34-0410-b5e6-96231b3b80d8

runtime/src/kmp_os.h

@@ -243,14 +243,16 @@ template <> struct traits_t<unsigned long long> {
 #define __forceinline __inline
 #endif
 
-#define PAGE_SIZE (0x4000)
+#if KMP_OS_WINDOWS
+#include <windows.h>
 
-#if KMP_OS_LINUX
-#define KMP_GET_PAGE_SIZE() getpagesize()
+static inline int KMP_GET_PAGE_SIZE(void) {
+    SYSTEM_INFO si;
+    GetSystemInfo(&si);
+    return si.dwPageSize;
+}
 #else
-// TODO: find the corresponding function to getpagesize() in Windows
-// and use it whenever possible.
-#define KMP_GET_PAGE_SIZE() PAGE_SIZE
+#define KMP_GET_PAGE_SIZE() getpagesize()
 #endif
 
 #define PAGE_ALIGNED(_addr)                                                    \
@@ -304,8 +306,6 @@ enum kmp_mem_fence_type {
 
 #if KMP_ASM_INTRINS && KMP_OS_WINDOWS
 
-#include <Windows.h>
-
 #pragma intrinsic(InterlockedExchangeAdd)
 #pragma intrinsic(InterlockedCompareExchange)
 #pragma intrinsic(InterlockedExchange)