build: separate compiler and libs

compiler/internal/lib/os/wait_waitid.go

@@ -0,0 +1,55 @@
+// Copyright 2016 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.
+
+// We used to used this code for Darwin, but according to issue #19314
+// waitid returns if the process is stopped, even when using WEXITED.
+
+//go:build linux
+
+package os
+
+import (
+	"syscall"
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+const _P_PID = 1
+
+// int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
+//
+//go:linkname waitid C.waitid
+func waitid(idtype, id uintptr, infop *uint64, options c.Int) c.Int
+
+// blockUntilWaitable attempts to block until a call to p.Wait will
+// succeed immediately, and reports whether it has done so.
+// It does not actually call p.Wait.
+func (p *Process) blockUntilWaitable() (bool, error) {
+	// The waitid system call expects a pointer to a siginfo_t,
+	// which is 128 bytes on all Linux systems.
+	// On darwin/amd64, it requires 104 bytes.
+	// We don't care about the values it returns.
+	var siginfo [16]uint64
+	psig := &siginfo[0]
+	var e syscall.Errno
+	for {
+		e = syscall.Errno(waitid(_P_PID, uintptr(p.Pid), psig, syscall.WEXITED|syscall.WNOWAIT))
+		if e != syscall.EINTR {
+			break
+		}
+	}
+	// TODO(xsw):
+	// runtime.KeepAlive(p)
+	if e != 0 {
+		// waitid has been available since Linux 2.6.9, but
+		// reportedly is not available in Ubuntu on Windows.
+		// See issue 16610.
+		if e == syscall.ENOSYS {
+			return false, nil
+		}
+		return false, NewSyscallError("waitid", e)
+	}
+	return true, nil
+}