syscall: don't generate ptrace on iOS

May fix #43302.

Change-Id: I6b7ddf94495c4fa80cf8a50a38eef5f8b2872669
Reviewed-on: https://go-review.googlesource.com/c/go/+/279481
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/syscall/mksyscall.pl

@@ -125,7 +125,7 @@ while(<>) {
 	# without reading the header.
 	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
 
-	if ($darwin && $func eq "ptrace") {
+	if ($darwin && $func eq "ptrace1") {
 		# The ptrace function is called from forkAndExecInChild where stack
 		# growth is forbidden.
 		$text .= "//go:nosplit\n"

src/syscall/ptrace_darwin.go

@@ -0,0 +1,14 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !ios
+
+package syscall
+
+// Nosplit because it is called from forkAndExecInChild.
+//
+//go:nosplit
+func ptrace(request int, pid int, addr uintptr, data uintptr) error {
+	return ptrace1(request, pid, addr, data)
+}

src/syscall/ptrace_ios.go

@@ -0,0 +1,12 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syscall
+
+// Nosplit because it is called from forkAndExecInChild.
+//
+//go:nosplit
+func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
+	panic("unimplemented")
+}

src/syscall/syscall_darwin_amd64.go

@@ -21,7 +21,7 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Stat(path string, stat *Stat_t) (err error) = SYS_stat64
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_statfs64
 //sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
-//sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
+//sys   ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) = SYS_ptrace
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)

src/syscall/syscall_darwin_arm64.go

@@ -21,7 +21,7 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Stat(path string, stat *Stat_t) (err error)
 //sys	Statfs(path string, stat *Statfs_t) (err error)
 //sys	fstatat(fd int, path string, stat *Stat_t, flags int) (err error)
-//sys	ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
+//sys	ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) = SYS_ptrace
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)

src/syscall/zsyscall_darwin_amd64.go

@@ -2091,7 +2091,7 @@ func libc_fstatat64_trampoline()
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
 //go:nosplit
-func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
+func ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(funcPC(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
 		err = errnoErr(e1)

src/syscall/zsyscall_darwin_arm64.go

@@ -2091,7 +2091,7 @@ func libc_fstatat_trampoline()
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
 //go:nosplit
-func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
+func ptrace1(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(funcPC(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
 		err = errnoErr(e1)