1// Copyright 2015 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package objabi
6
7import (
8	"fmt"
9	"log"
10	"os"
11	"strings"
12)
13
14func envOr(key, value string) string {
15	if x := os.Getenv(key); x != "" {
16		return x
17	}
18	return value
19}
20
21var (
22	defaultGOROOT string // set by linker
23
24	GOROOT   = envOr("GOROOT", defaultGOROOT)
25	GOARCH   = envOr("GOARCH", defaultGOARCH)
26	GOOS     = envOr("GOOS", defaultGOOS)
27	GO386    = envOr("GO386", defaultGO386)
28	GOARM    = goarm()
29	GOMIPS   = gomips()
30	GOMIPS64 = gomips64()
31	Version  = version
32)
33
34func goarm() int {
35	switch v := envOr("GOARM", defaultGOARM); v {
36	case "5":
37		return 5
38	case "6":
39		return 6
40	case "7":
41		return 7
42	}
43	// Fail here, rather than validate at multiple call sites.
44	log.Fatalf("Invalid GOARM value. Must be 5, 6, or 7.")
45	panic("unreachable")
46}
47
48func gomips() string {
49	switch v := envOr("GOMIPS", defaultGOMIPS); v {
50	case "hardfloat", "softfloat":
51		return v
52	}
53	log.Fatalf("Invalid GOMIPS value. Must be hardfloat or softfloat.")
54	panic("unreachable")
55}
56
57func gomips64() string {
58	switch v := envOr("GOMIPS64", defaultGOMIPS64); v {
59	case "hardfloat", "softfloat":
60		return v
61	}
62	log.Fatalf("Invalid GOMIPS64 value. Must be hardfloat or softfloat.")
63	panic("unreachable")
64}
65
66func Getgoextlinkenabled() string {
67	return envOr("GO_EXTLINK_ENABLED", defaultGO_EXTLINK_ENABLED)
68}
69
70func init() {
71	for _, f := range strings.Split(goexperiment, ",") {
72		if f != "" {
73			addexp(f)
74		}
75	}
76}
77
78func Framepointer_enabled(goos, goarch string) bool {
79	return framepointer_enabled != 0 && (goarch == "amd64" && goos != "nacl" || goarch == "arm64" && goos == "linux")
80}
81
82func addexp(s string) {
83	// Could do general integer parsing here, but the runtime copy doesn't yet.
84	v := 1
85	name := s
86	if len(name) > 2 && name[:2] == "no" {
87		v = 0
88		name = name[2:]
89	}
90	for i := 0; i < len(exper); i++ {
91		if exper[i].name == name {
92			if exper[i].val != nil {
93				*exper[i].val = v
94			}
95			return
96		}
97	}
98
99	fmt.Printf("unknown experiment %s\n", s)
100	os.Exit(2)
101}
102
103var (
104	framepointer_enabled     int = 1
105	Fieldtrack_enabled       int
106	Preemptibleloops_enabled int
107)
108
109// Toolchain experiments.
110// These are controlled by the GOEXPERIMENT environment
111// variable recorded when the toolchain is built.
112// This list is also known to cmd/gc.
113var exper = []struct {
114	name string
115	val  *int
116}{
117	{"fieldtrack", &Fieldtrack_enabled},
118	{"framepointer", &framepointer_enabled},
119	{"preemptibleloops", &Preemptibleloops_enabled},
120}
121
122var defaultExpstring = Expstring()
123
124func DefaultExpstring() string {
125	return defaultExpstring
126}
127
128func Expstring() string {
129	buf := "X"
130	for i := range exper {
131		if *exper[i].val != 0 {
132			buf += "," + exper[i].name
133		}
134	}
135	if buf == "X" {
136		buf += ",none"
137	}
138	return "X:" + buf[2:]
139}
140