AppleHV enablement pass #2

* Use vfkit command line assembly
* Inject ignition file into guest using http over vsock
* Ready notification through use of vsock

[NO NEW TESTS NEEDED]

Signed-off-by: Brent Baude <bbaude@redhat.com>

vendor/github.com/twitchyliquid64/golang-asm/objabi/util.go

@@ -0,0 +1,203 @@
+// Copyright 2015 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 objabi
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+func envOr(key, value string) string {
+	if x := os.Getenv(key); x != "" {
+		return x
+	}
+	return value
+}
+
+var (
+	defaultGOROOT string // set by linker
+
+	GOROOT   = envOr("GOROOT", defaultGOROOT)
+	GOARCH   = envOr("GOARCH", "amd64")
+	GOOS     = envOr("GOOS", "linux")
+	GO386    = envOr("GO386", "")
+	GOAMD64  = goamd64()
+	GOARM    = goarm()
+	GOMIPS   = gomips()
+	GOMIPS64 = gomips64()
+	GOPPC64  = goppc64()
+	GOWASM   = gowasm()
+	GO_LDSO  = ""
+	Version  = ""
+)
+
+const (
+	ElfRelocOffset   = 256
+	MachoRelocOffset = 2048           // reserve enough space for ELF relocations
+	Go115AMD64       = "alignedjumps" // Should be "alignedjumps" or "normaljumps"; this replaces environment variable introduced in CL 219357.
+)
+
+// TODO(1.16): assuming no issues in 1.15 release, remove this and related constant.
+func goamd64() string {
+	return Go115AMD64
+}
+
+func goarm() int {
+	switch v := envOr("GOARM", "7"); v {
+	case "5":
+		return 5
+	case "6":
+		return 6
+	case "7":
+		return 7
+	}
+	// Fail here, rather than validate at multiple call sites.
+	log.Fatalf("Invalid GOARM value. Must be 5, 6, or 7.")
+	panic("unreachable")
+}
+
+func gomips() string {
+	switch v := envOr("GOMIPS", "hardfloat"); v {
+	case "hardfloat", "softfloat":
+		return v
+	}
+	log.Fatalf("Invalid GOMIPS value. Must be hardfloat or softfloat.")
+	panic("unreachable")
+}
+
+func gomips64() string {
+	switch v := envOr("GOMIPS64", "hardfloat"); v {
+	case "hardfloat", "softfloat":
+		return v
+	}
+	log.Fatalf("Invalid GOMIPS64 value. Must be hardfloat or softfloat.")
+	panic("unreachable")
+}
+
+func goppc64() int {
+	switch v := envOr("GOPPC64", "power8"); v {
+	case "power8":
+		return 8
+	case "power9":
+		return 9
+	}
+	log.Fatalf("Invalid GOPPC64 value. Must be power8 or power9.")
+	panic("unreachable")
+}
+
+type gowasmFeatures struct {
+	SignExt bool
+	SatConv bool
+}
+
+func (f gowasmFeatures) String() string {
+	var flags []string
+	if f.SatConv {
+		flags = append(flags, "satconv")
+	}
+	if f.SignExt {
+		flags = append(flags, "signext")
+	}
+	return strings.Join(flags, ",")
+}
+
+func gowasm() (f gowasmFeatures) {
+	for _, opt := range strings.Split(envOr("GOWASM", ""), ",") {
+		switch opt {
+		case "satconv":
+			f.SatConv = true
+		case "signext":
+			f.SignExt = true
+		case "":
+			// ignore
+		default:
+			log.Fatalf("Invalid GOWASM value. No such feature: " + opt)
+		}
+	}
+	return
+}
+
+func Getgoextlinkenabled() string {
+	return envOr("GO_EXTLINK_ENABLED", "")
+}
+
+func init() {
+	for _, f := range strings.Split("", ",") {
+		if f != "" {
+			addexp(f)
+		}
+	}
+
+	// regabi is only supported on amd64.
+	if GOARCH != "amd64" {
+		Regabi_enabled = 0
+	}
+}
+
+// Note: must agree with runtime.framepointer_enabled.
+var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin")
+
+func addexp(s string) {
+	// Could do general integer parsing here, but the runtime copy doesn't yet.
+	v := 1
+	name := s
+	if len(name) > 2 && name[:2] == "no" {
+		v = 0
+		name = name[2:]
+	}
+	for i := 0; i < len(exper); i++ {
+		if exper[i].name == name {
+			if exper[i].val != nil {
+				*exper[i].val = v
+			}
+			return
+		}
+	}
+
+	fmt.Printf("unknown experiment %s\n", s)
+	os.Exit(2)
+}
+
+var (
+	Fieldtrack_enabled        int
+	Preemptibleloops_enabled  int
+	Staticlockranking_enabled int
+	Regabi_enabled            int
+)
+
+// Toolchain experiments.
+// These are controlled by the GOEXPERIMENT environment
+// variable recorded when the toolchain is built.
+// This list is also known to cmd/gc.
+var exper = []struct {
+	name string
+	val  *int
+}{
+	{"fieldtrack", &Fieldtrack_enabled},
+	{"preemptibleloops", &Preemptibleloops_enabled},
+	{"staticlockranking", &Staticlockranking_enabled},
+	{"regabi", &Regabi_enabled},
+}
+
+var defaultExpstring = Expstring()
+
+func DefaultExpstring() string {
+	return defaultExpstring
+}
+
+func Expstring() string {
+	buf := "X"
+	for i := range exper {
+		if *exper[i].val != 0 {
+			buf += "," + exper[i].name
+		}
+	}
+	if buf == "X" {
+		buf += ",none"
+	}
+	return "X:" + buf[2:]
+}