1// Copyright 2017 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
5// Build initialization (after flag parsing).
6
7package work
8
9import (
10	"cmd/go/internal/base"
11	"cmd/go/internal/cfg"
12	"cmd/go/internal/load"
13	"cmd/internal/sys"
14	"flag"
15	"fmt"
16	"os"
17	"path/filepath"
18	"strings"
19)
20
21func BuildInit() {
22	load.ModInit()
23	instrumentInit()
24	buildModeInit()
25
26	// Make sure -pkgdir is absolute, because we run commands
27	// in different directories.
28	if cfg.BuildPkgdir != "" && !filepath.IsAbs(cfg.BuildPkgdir) {
29		p, err := filepath.Abs(cfg.BuildPkgdir)
30		if err != nil {
31			fmt.Fprintf(os.Stderr, "go %s: evaluating -pkgdir: %v\n", flag.Args()[0], err)
32			base.SetExitStatus(2)
33			base.Exit()
34		}
35		cfg.BuildPkgdir = p
36	}
37}
38
39func instrumentInit() {
40	if !cfg.BuildRace && !cfg.BuildMSan {
41		return
42	}
43	if cfg.BuildRace && cfg.BuildMSan {
44		fmt.Fprintf(os.Stderr, "go %s: may not use -race and -msan simultaneously\n", flag.Args()[0])
45		base.SetExitStatus(2)
46		base.Exit()
47	}
48	if cfg.BuildMSan && !sys.MSanSupported(cfg.Goos, cfg.Goarch) {
49		fmt.Fprintf(os.Stderr, "-msan is not supported on %s/%s\n", cfg.Goos, cfg.Goarch)
50		base.SetExitStatus(2)
51		base.Exit()
52	}
53	if cfg.BuildRace {
54		if !sys.RaceDetectorSupported(cfg.Goos, cfg.Goarch) {
55			fmt.Fprintf(os.Stderr, "go %s: -race is only supported on linux/amd64, linux/ppc64le, linux/arm64, freebsd/amd64, netbsd/amd64, darwin/amd64 and windows/amd64\n", flag.Args()[0])
56			base.SetExitStatus(2)
57			base.Exit()
58		}
59	}
60	mode := "race"
61	if cfg.BuildMSan {
62		mode = "msan"
63		// MSAN does not support non-PIE binaries on ARM64.
64		// See issue #33712 for details.
65		if cfg.Goos == "linux" && cfg.Goarch == "arm64" && cfg.BuildBuildmode == "default" {
66			cfg.BuildBuildmode = "pie"
67		}
68	}
69	modeFlag := "-" + mode
70
71	if !cfg.BuildContext.CgoEnabled {
72		fmt.Fprintf(os.Stderr, "go %s: %s requires cgo; enable cgo by setting CGO_ENABLED=1\n", flag.Args()[0], modeFlag)
73		base.SetExitStatus(2)
74		base.Exit()
75	}
76	forcedGcflags = append(forcedGcflags, modeFlag)
77	forcedLdflags = append(forcedLdflags, modeFlag)
78
79	if cfg.BuildContext.InstallSuffix != "" {
80		cfg.BuildContext.InstallSuffix += "_"
81	}
82	cfg.BuildContext.InstallSuffix += mode
83	cfg.BuildContext.BuildTags = append(cfg.BuildContext.BuildTags, mode)
84}
85
86func buildModeInit() {
87	gccgo := cfg.BuildToolchainName == "gccgo"
88	var codegenArg string
89
90	// Configure the build mode first, then verify that it is supported.
91	// That way, if the flag is completely bogus we will prefer to error out with
92	// "-buildmode=%s not supported" instead of naming the specific platform.
93
94	switch cfg.BuildBuildmode {
95	case "archive":
96		pkgsFilter = pkgsNotMain
97	case "c-archive":
98		pkgsFilter = oneMainPkg
99		if gccgo {
100			codegenArg = "-fPIC"
101		} else {
102			switch cfg.Goos {
103			case "darwin":
104				switch cfg.Goarch {
105				case "arm", "arm64":
106					codegenArg = "-shared"
107				}
108
109			case "dragonfly", "freebsd", "illumos", "linux", "netbsd", "openbsd", "solaris":
110				// Use -shared so that the result is
111				// suitable for inclusion in a PIE or
112				// shared library.
113				codegenArg = "-shared"
114			}
115		}
116		cfg.ExeSuffix = ".a"
117		ldBuildmode = "c-archive"
118	case "c-shared":
119		pkgsFilter = oneMainPkg
120		if gccgo {
121			codegenArg = "-fPIC"
122		} else {
123			switch cfg.Goos {
124			case "linux", "android", "freebsd":
125				codegenArg = "-shared"
126			case "windows":
127				// Do not add usual .exe suffix to the .dll file.
128				cfg.ExeSuffix = ""
129			}
130		}
131		ldBuildmode = "c-shared"
132	case "default":
133		switch cfg.Goos {
134		case "android":
135			codegenArg = "-shared"
136			ldBuildmode = "pie"
137		case "darwin":
138			switch cfg.Goarch {
139			case "arm", "arm64":
140				codegenArg = "-shared"
141			}
142			fallthrough
143		default:
144			ldBuildmode = "exe"
145		}
146		if gccgo {
147			codegenArg = ""
148		}
149	case "exe":
150		pkgsFilter = pkgsMain
151		ldBuildmode = "exe"
152		// Set the pkgsFilter to oneMainPkg if the user passed a specific binary output
153		// and is using buildmode=exe for a better error message.
154		// See issue #20017.
155		if cfg.BuildO != "" {
156			pkgsFilter = oneMainPkg
157		}
158	case "pie":
159		if cfg.BuildRace {
160			base.Fatalf("-buildmode=pie not supported when -race is enabled")
161		}
162		if gccgo {
163			codegenArg = "-fPIE"
164		} else if cfg.Goos != "aix" {
165			codegenArg = "-shared"
166		}
167		ldBuildmode = "pie"
168	case "shared":
169		pkgsFilter = pkgsNotMain
170		if gccgo {
171			codegenArg = "-fPIC"
172		} else {
173			codegenArg = "-dynlink"
174		}
175		if cfg.BuildO != "" {
176			base.Fatalf("-buildmode=shared and -o not supported together")
177		}
178		ldBuildmode = "shared"
179	case "plugin":
180		pkgsFilter = oneMainPkg
181		if gccgo {
182			codegenArg = "-fPIC"
183		} else {
184			codegenArg = "-dynlink"
185		}
186		cfg.ExeSuffix = ".so"
187		ldBuildmode = "plugin"
188	default:
189		base.Fatalf("buildmode=%s not supported", cfg.BuildBuildmode)
190	}
191
192	if !sys.BuildModeSupported(cfg.BuildToolchainName, cfg.BuildBuildmode, cfg.Goos, cfg.Goarch) {
193		base.Fatalf("-buildmode=%s not supported on %s/%s\n", cfg.BuildBuildmode, cfg.Goos, cfg.Goarch)
194	}
195
196	if cfg.BuildLinkshared {
197		if !sys.BuildModeSupported(cfg.BuildToolchainName, "shared", cfg.Goos, cfg.Goarch) {
198			base.Fatalf("-linkshared not supported on %s/%s\n", cfg.Goos, cfg.Goarch)
199		}
200		if gccgo {
201			codegenArg = "-fPIC"
202		} else {
203			forcedAsmflags = append(forcedAsmflags, "-D=GOBUILDMODE_shared=1")
204			codegenArg = "-dynlink"
205			forcedGcflags = append(forcedGcflags, "-linkshared")
206			// TODO(mwhudson): remove -w when that gets fixed in linker.
207			forcedLdflags = append(forcedLdflags, "-linkshared", "-w")
208		}
209	}
210	if codegenArg != "" {
211		if gccgo {
212			forcedGccgoflags = append([]string{codegenArg}, forcedGccgoflags...)
213		} else {
214			forcedAsmflags = append([]string{codegenArg}, forcedAsmflags...)
215			forcedGcflags = append([]string{codegenArg}, forcedGcflags...)
216		}
217		// Don't alter InstallSuffix when modifying default codegen args.
218		if cfg.BuildBuildmode != "default" || cfg.BuildLinkshared {
219			if cfg.BuildContext.InstallSuffix != "" {
220				cfg.BuildContext.InstallSuffix += "_"
221			}
222			cfg.BuildContext.InstallSuffix += codegenArg[1:]
223		}
224	}
225
226	switch cfg.BuildMod {
227	case "":
228		// ok
229	case "readonly", "vendor", "mod":
230		if !cfg.ModulesEnabled && !inGOFLAGS("-mod") {
231			base.Fatalf("build flag -mod=%s only valid when using modules", cfg.BuildMod)
232		}
233	default:
234		base.Fatalf("-mod=%s not supported (can be '', 'mod', 'readonly', or 'vendor')", cfg.BuildMod)
235	}
236	if !cfg.ModulesEnabled {
237		if cfg.ModCacheRW && !inGOFLAGS("-modcacherw") {
238			base.Fatalf("build flag -modcacherw only valid when using modules")
239		}
240		if cfg.ModFile != "" && !inGOFLAGS("-mod") {
241			base.Fatalf("build flag -modfile only valid when using modules")
242		}
243	}
244}
245
246func inGOFLAGS(flag string) bool {
247	for _, goflag := range base.GOFLAGS() {
248		name := goflag
249		if strings.HasPrefix(name, "--") {
250			name = name[1:]
251		}
252		if i := strings.Index(name, "="); i >= 0 {
253			name = name[:i]
254		}
255		if name == flag {
256			return true
257		}
258	}
259	return false
260}
261