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	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)
//sysnb exit(res int) (err error)

//sys	Unmount(path string, flags int) (err error)
//sys	write(fd int, p []byte) (n int, 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)
//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)

const (
	mremapFixed     = MAP_FIXED
	mremapDontunmap = 0
	mremapMaymove   = 0
)

//sys	Unmount(path string, flags int) (err error)
//sys	write(fd int, p []byte) (n int, 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)
//sys	accept4(fd int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (nfd int, err error)

//sys	Unmount(path string, flags int) (err error)
//sys	write(fd int, p []byte) (n int, 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)
//sys	getfsstat(stat *Statfs_t, bufsize uintptr, flags int) (n int, err error)
//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)

	// to code generation.
	bench.Start("GenSymsLate")
	if thearch.GenSymsLate != nil {
		thearch.GenSymsLate(ctxt, ctxt.loader)
	}

	bench.Start("Asmb2")
	asmb2(ctxt)

	bench.Start("Munmap")
	ctxt.Out.Close() // Close handles Munmapping if necessary.

	bench.Start("hostlink")
	ctxt.hostlink()
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%s", ctxt.loader.Stat())

	ECALL
	MOV	$-4096, T0
	BGEU	T0, A0, 5(PC)
	SUB	A0, ZERO, A0
	MOV	ZERO, p+32(FP)
	MOV	A0, err+40(FP)
	RET
ok:
	MOV	A0, p+32(FP)
	MOV	ZERO, err+40(FP)
	RET

// func munmap(addr unsafe.Pointer, n uintptr)
TEXT runtime·munmap(SB),NOSPLIT|NOFRAME,$0
	MOV	addr+0(FP), A0
	MOV	n+8(FP), A1
	MOV	$SYS_munmap, A7
	ECALL
	MOV	$-4096, T0
	BLTU	A0, T0, 2(PC)
	WORD	$0	// crash
	RET

	n = int(r0)
	if r0 == -1 && er != nil {
		err = er
	}
	return
}

// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT

func munmap(addr uintptr, length uintptr) (err error) {
	r0, er := C.munmap(C.uintptr_t(addr), C.uintptr_t(length))
	if r0 == -1 && er != nil {
		err = er
	}
	return
}

// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT

	SYS_SSTK                     = 70  // { int sstk(int incr); }
	SYS_OVADVISE                 = 72  // { int ovadvise(int anom); } vadvise \
	SYS_MUNMAP                   = 73  // { int munmap(void *addr, size_t len); }
	SYS_MPROTECT                 = 74  // { int mprotect(const void *addr, size_t len, \
	SYS_MADVISE                  = 75  // { int madvise(void *addr, size_t len, \

	SYS_SSTK                     = 70  // { int sstk(int incr); }
	SYS_OVADVISE                 = 72  // { int ovadvise(int anom); } vadvise \
	SYS_MUNMAP                   = 73  // { int munmap(void *addr, size_t len); }
	SYS_MPROTECT                 = 74  // { int mprotect(const void *addr, size_t len, \
	SYS_MADVISE                  = 75  // { int madvise(void *addr, size_t len, \