Use MAP_JIT flag when allocating executable memory on macOS ARM64.

Author: TautvydasZilys

mono/utils/dlmalloc.c

@@ -1314,7 +1314,14 @@ extern void*     sbrk(ptrdiff_t);
 #define MAP_ANONYMOUS        MAP_ANON
 #endif /* MAP_ANON */
 #ifdef MAP_ANONYMOUS
+
+#if defined(__APPLE__) && defined(__arm64__)
+/* macOS on ARM64 requires using MAP_JIT in order to allocate executable memory. */
+#define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS|MAP_JIT)
+#else
 #define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS)
+#endif
+
 #define CALL_MMAP(s)         mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
 #else /* MAP_ANONYMOUS */
 /*

mono/utils/mono-mmap.c

@@ -228,6 +228,13 @@ mono_valloc (void *addr, size_t length, int flags, MonoMemAccountType type)
 	mflags |= MAP_ANONYMOUS;
 	mflags |= MAP_PRIVATE;
 
+#if defined(__APPLE__) && defined(__arm64__)
+	/* macOS on ARM64 requires using MAP_JIT in order
+	   to allocate executable memory. */
+	if (type == MONO_MEM_ACCOUNT_CODE)
+		mflags |= MAP_JIT;
+#endif
+
 	BEGIN_CRITICAL_SECTION;
 	ptr = mmap (addr, length, prot, mflags, -1, 0);
 	if (ptr == MAP_FAILED) {