Function Build

builder/build.go:100–1087

Build performs a single package to executable Go build. It takes in a package name, an output path, and set of compile options and from that it manages the whole compilation process. The error value may be of type *MultiError. Callers will likely want to check for this case and print such errors in

(pkgName, outpath, tmpdir string, config *compileopts.Config)

// The error value may be of type *MultiError. Callers will likely want to check
// for this case and print such errors individually.
func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildResult, error) {
	// Read the build ID of the tinygo binary.
	// Used as a cache key for package builds.
	compilerBuildID, err := ReadBuildID()
	if err != nil {
		return BuildResult{}, err
	}

	if config.Options.Work {
		fmt.Printf("WORK=%s\n", tmpdir)
	}

	// Look up the build cache directory, which is used to speed up incremental
	// builds.
	cacheDir := goenv.Get("GOCACHE")
	if cacheDir == "off" {
		// Use temporary build directory instead, effectively disabling the
		// build cache.
		cacheDir = tmpdir
	}

	// Create default global values.
	globalValues := map[string]map[string]string{
		"runtime": {
			"buildVersion": goenv.Version(),
		},
		"testing": {},
	}
	if config.TestConfig.CompileTestBinary {
		// The testing.testBinary is set to "1" when in a test.
		// This is needed for testing.Testing() to work correctly.
		globalValues["testing"]["testBinary"] = "1"
	}

	// Copy over explicitly set global values, like
	// -ldflags="-X main.Version="1.0"
	for pkgPath, vals := range config.Options.GlobalValues {
		if _, ok := globalValues[pkgPath]; !ok {
			globalValues[pkgPath] = map[string]string{}
		}
		for k, v := range vals {
			globalValues[pkgPath][k] = v
		}
	}

	// Check for a libc dependency.
	// As a side effect, this also creates the headers for the given libc, if
	// the libc needs them.
	root := goenv.Get("TINYGOROOT")
	var libcDependencies []*compileJob
	switch config.Target.Libc {
	case "darwin-libSystem":
		libcJob := makeDarwinLibSystemJob(config, tmpdir)
		libcDependencies = append(libcDependencies, libcJob)
	case "musl":
		var unlock func()
		libcJob, unlock, err := libMusl.load(config, tmpdir)
		if err != nil {