}

func (m *mmapper) Munmap(data []byte) (err error) {
	if len(data) == 0 || len(data) != cap(data) {
		return EINVAL
	}

	// Find the base of the mapping.
	p := &data[cap(data)-1]
	m.Lock()
	defer m.Unlock()
	b := m.active[p]
	if b == nil || &b[0] != &data[0] {
		return EINVAL
	}

	// Unmap the memory and update m.
	if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != nil {
		return errno

		// Since Linux 3.18, support for madvise is optional.
		// Fall back on mmap if it's not supported.
		// _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE will unmap all the
		// pages in the old mapping, and remap the memory region.
		mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
	}

	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
		if p != v || err != 0 {

		// bump start to next page
		start = round(limit, pageSize)
	}
	return start, start + n
}

var memmap = mmap.Mmap
var munmap = mmap.Munmap

func (m *mappedFile) close() {
	m.closeOnce.Do(func() {
		if m.mapping != nil {
			munmap(m.mapping)
			m.mapping = nil
		}
		if m.f != nil {
			m.f.Close() // best effort
			m.f = nil
		}
	})
}

//go:cgo_import_dynamic libc_kill kill "libc.so"
//go:cgo_import_dynamic libc_madvise madvise "libc.so"
//go:cgo_import_dynamic libc_malloc malloc "libc.so"
//go:cgo_import_dynamic libc_mmap mmap "libc.so"
//go:cgo_import_dynamic libc_munmap munmap "libc.so"
//go:cgo_import_dynamic libc_open open "libc.so"
//go:cgo_import_dynamic libc_pthread_attr_destroy pthread_attr_destroy "libc.so"

// mmap varies by architecture; see syscall_linux_*.go.
//sys	munmap(addr uintptr, length uintptr) (err error)

var mapper = &mmapper{
	active: make(map[*byte][]byte),
	mmap:   mmap,
	munmap: munmap,
}

func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
	return mapper.Mmap(fd, offset, length, prot, flags)
}

	}
	return
}
func osinit_hack_trampoline()

// mmap is used to do low-level memory allocation via mmap. Don't allow stack
// splits, since this function (used by sysAlloc) is called in a lot of low-level
// parts of the runtime and callers often assume it won't acquire any locks.
//
//go:nosplit
func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (unsafe.Pointer, int) {

  const void* const address;
  const uint64_t length;
} PosixMemoryRegion;

static void Cleanup(TF_ReadOnlyMemoryRegion* region) {
  auto r = static_cast<PosixMemoryRegion*>(region->plugin_memory_region);
  munmap(const_cast<void*>(r->address), r->length);
  delete r;
}

static const void* Data(const TF_ReadOnlyMemoryRegion* region) {
  auto r = static_cast<PosixMemoryRegion*>(region->plugin_memory_region);

//sys	Unmount(path string, flags int) (err error)
//sys	write(fd int, p []byte) (n int, err error)
//sys	writev(fd int, iovecs []Iovec) (cnt uintptr, err error)
//sys   mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
//sys   munmap(addr uintptr, length uintptr) (err error)
//sysnb fork() (pid int, err error)
//sysnb execve(path *byte, argv **byte, envp **byte) (err error)

func Madvise(b []byte, advice int) (err error) {
	return
}

func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
	return mapper.Mmap(fd, offset, length, prot, flags)
}

func Munmap(b []byte) (err error) {
	return mapper.Munmap(b)
}

//sys   Gethostname(buf []byte) (err error) = SYS___GETHOSTNAME_A
//sysnb	Getgid() (gid int)

	// which we don't know the size.
	if ctxt.Arch.Family != sys.Wasm {
		// Don't mmap if we're building for Wasm. Wasm file
		// layout is very different so filesize is meaningless.
		if err := ctxt.Out.Mmap(filesize); err != nil {
			Exitf("mapping output file failed: %v", err)
		}
	}
	// asmb will redirect symbols to the output file mmap, and relocations
	// will be applied directly there.
	bench.Start("Asmb")
	asmb(ctxt)