fix for mac and enable it if XBYAK_MEMFD_CREATE is defined

1 files changed, 10 insertions, 16 deletions

diff --git a/xbyak/xbyak.h b/xbyak/xbyak.h
index 503a3fa..bb57007 100644
--- a/xbyak/xbyak.h
+++ b/xbyak/xbyak.h
@@ -79,7 +79,6 @@
 	#include <malloc.h>
 	#define XBYAK_TLS __declspec(thread)
 #elif defined(__GNUC__)
-	#include <syscall.h>
 	#include <unistd.h>
 	#include <sys/mman.h>
 	#include <stdlib.h>
@@ -96,6 +95,10 @@
 	#include <stdint.h>
 #endif
 
+#if !defined(MFD_CLOEXEC) // defined only linux 3.17 or later
+	#undef XBYAK_MEMFD_CREATE
+#endif
+
 #if defined(_WIN64) || defined(__MINGW64__) || (defined(__CYGWIN__) && defined(__x86_64__))
 	#define XBYAK64_WIN
 #elif defined(__x86_64__)
@@ -414,26 +417,11 @@ inline int getMacOsVersion()
 class MmapAllocator : Allocator {
 	typedef XBYAK_STD_UNORDERED_MAP<uintptr_t, size_t> SizeList;
 	SizeList sizeList_;
-
-	static int memfd_fd()
-	{
-#ifdef __NR_memfd_create
-#ifdef MFD_CLOEXEC
-		int flags = MFD_CLOEXEC;
-#else
-		int flags = 0;
-#endif
-		return syscall(__NR_memfd_create, "xbyak", flags);
-#else
-		return -1;
-#endif
-	}
 public:
 	uint8_t *alloc(size_t size)
 	{
 		const size_t alignedSizeM1 = inner::ALIGN_PAGE_SIZE - 1;
 		size = (size + alignedSizeM1) & ~alignedSizeM1;
-		int fd = memfd_fd();
 #if defined(MAP_ANONYMOUS)
 		int mode = MAP_PRIVATE | MAP_ANONYMOUS;
 #elif defined(MAP_ANON)
@@ -445,12 +433,18 @@ public:
 		const int mojaveVersion = 18;
 		if (util::getMacOsVersion() >= mojaveVersion) mode |= MAP_JIT;
 #endif
+		int fd = -1;
+#if defined(XBYAK_MEMFD_CREATE) && XBYAK_MEMFD_CREATE == 1
+		fd = memfd_create("xbyak", MFD_CLOEXEC);
 		if (fd != -1) {
 			mode = MAP_SHARED;
 			if (ftruncate(fd, size) != 0) XBYAK_THROW_RET(ERR_CANT_ALLOC, 0)
 		}
+#endif
 		void *p = mmap(NULL, size, PROT_READ | PROT_WRITE, mode, fd, 0);
+#if defined(XBYAK_MEMFD_CREATE) && XBYAK_MEMFD_CREATE == 1
 		if (fd != -1) close(fd);
+#endif
 		if (p == MAP_FAILED) XBYAK_THROW_RET(ERR_CANT_ALLOC, 0)
 		assert(p);
 		sizeList_[(uintptr_t)p] = size;