golang buildruntime 代码
文件路径：/src/cmd/dist/buildruntime.go
/ Copyright 2012 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 main
import (
"bytes"
"fmt"
"os"
"strings"
)
/*
* Helpers for building runtime.
*/
/ mkzversion writes zversion.go:
/
/ package sys
/
/ const StackGuardMultiplier = <multiplier value>
func mkzversion(dir, file string) {
var buf bytes.Buffer
fmt.Fprintf(&buf, "/ Code generated by go tool dist; DO NOT EDIT.\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "package sys\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "const StackGuardMultiplierDefault = %d\n", stackGuardMultiplierDefault())
writefile(buf.String(), file, writeSkipSame)
}
/ mkbuildcfg writes internal/buildcfg/zbootstrap.go:
/
/ package buildcfg
/
/ const defaultGOROOT = <goroot>
/ const defaultGO386 = <go386>
/ ...
/ const defaultGOOS = runtime.GOOS
/ const defaultGOARCH = runtime.GOARCH
/
/ The use of runtime.GOOS and runtime.GOARCH makes sure that
/ a cross-compiled compiler expects to compile for its own target
/ system. That is, if on a Mac you do:
/
/ GOOS=linux GOARCH=ppc64 go build cmd/compile
/
/ the resulting compiler will default to generating linux/ppc64 object files.
/ This is more useful than having it default to generating objects for the
/ original target (in this example, a Mac).
func mkbuildcfg(file string) {
var buf bytes.Buffer
fmt.Fprintf(&buf, "/ Code generated by go tool dist; DO NOT EDIT.\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "package buildcfg\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "import \"runtime\"\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "const defaultGO386 = `%s`\n", go386)
fmt.Fprintf(&buf, "const defaultGOAMD64 = `%s`\n", goamd64)
fmt.Fprintf(&buf, "const defaultGOARM = `%s`\n", goarm)
fmt.Fprintf(&buf, "const defaultGOMIPS = `%s`\n", gomips)
fmt.Fprintf(&buf, "const defaultGOMIPS64 = `%s`\n", gomips64)
fmt.Fprintf(&buf, "const defaultGOPPC64 = `%s`\n", goppc64)
fmt.Fprintf(&buf, "const defaultGOEXPERIMENT = `%s`\n", goexperiment)
fmt.Fprintf(&buf, "const defaultGO_EXTLINK_ENABLED = `%s`\n", goextlinkenabled)
fmt.Fprintf(&buf, "const defaultGO_LDSO = `%s`\n", defaultldso)
fmt.Fprintf(&buf, "const version = `%s`\n", findgoversion())
fmt.Fprintf(&buf, "const defaultGOOS = runtime.GOOS\n")
fmt.Fprintf(&buf, "const defaultGOARCH = runtime.GOARCH\n")
writefile(buf.String(), file, writeSkipSame)
}
/ mkobjabi writes cmd/internal/objabi/zbootstrap.go:
/
/ package objabi
/
/ const stackGuardMultiplierDefault = <multiplier value>
func mkobjabi(file string) {
var buf bytes.Buffer
fmt.Fprintf(&buf, "/ Code generated by go tool dist; DO NOT EDIT.\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "package objabi\n")
fmt.Fprintln(&buf)
fmt.Fprintf(&buf, "const stackGuardMultiplierDefault = %d\n", stackGuardMultiplierDefault())
writefile(buf.String(), file, writeSkipSame)
}
/ stackGuardMultiplierDefault returns a multiplier to apply to the default
/ stack guard size. Larger multipliers are used for non-optimized
/ builds that have larger stack frames.
func stackGuardMultiplierDefault() int {
for _, s := range strings.Split(os.Getenv("GO_GCFLAGS"), " ") {
if s == "-N" {
return 2
}
}
return 1
}