github.com/4ad/go@v0.0.0-20161219182952-69a12818b605/src/cmd/dist/buildruntime.go (about)

     1  // Copyright 2012 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  package main
     6  
     7  import (
     8  	"fmt"
     9  	"os"
    10  	"strings"
    11  )
    12  
    13  /*
    14   * Helpers for building runtime.
    15   */
    16  
    17  // mkzversion writes zversion.go:
    18  //
    19  //	package sys
    20  //	const DefaultGoroot = <goroot>
    21  //	const TheVersion = <version>
    22  //	const Goexperiment = <goexperiment>
    23  //	const StackGuardMultiplier = <multiplier value>
    24  //
    25  func mkzversion(dir, file string) {
    26  	out := fmt.Sprintf(
    27  		"// auto generated by go tool dist\n"+
    28  			"\n"+
    29  			"package sys\n"+
    30  			"\n"+
    31  			"const DefaultGoroot = `%s`\n"+
    32  			"const TheVersion = `%s`\n"+
    33  			"const Goexperiment = `%s`\n"+
    34  			"const StackGuardMultiplier = %d\n\n", goroot_final, findgoversion(), os.Getenv("GOEXPERIMENT"), stackGuardMultiplier())
    35  
    36  	writefile(out, file, writeSkipSame)
    37  }
    38  
    39  // mkzbootstrap writes cmd/internal/obj/zbootstrap.go:
    40  //
    41  //	package obj
    42  //
    43  //	const defaultGOROOT = <goroot>
    44  //	const defaultGO386 = <go386>
    45  //	const defaultGOARM = <goarm>
    46  //	const defaultGOOS = runtime.GOOS
    47  //	const defaultGOARCH = runtime.GOARCH
    48  //	const defaultGO_EXTLINK_ENABLED = <goextlinkenabled>
    49  //	const version = <version>
    50  //	const stackGuardMultiplier = <multiplier value>
    51  //	const goexperiment = <goexperiment>
    52  //
    53  // The use of runtime.GOOS and runtime.GOARCH makes sure that
    54  // a cross-compiled compiler expects to compile for its own target
    55  // system. That is, if on a Mac you do:
    56  //
    57  //	GOOS=linux GOARCH=ppc64 go build cmd/compile
    58  //
    59  // the resulting compiler will default to generating linux/ppc64 object files.
    60  // This is more useful than having it default to generating objects for the
    61  // original target (in this example, a Mac).
    62  func mkzbootstrap(file string) {
    63  	out := fmt.Sprintf(
    64  		"// auto generated by go tool dist\n"+
    65  			"\n"+
    66  			"package obj\n"+
    67  			"\n"+
    68  			"import \"runtime\"\n"+
    69  			"\n"+
    70  			"const defaultGOROOT = `%s`\n"+
    71  			"const defaultGO386 = `%s`\n"+
    72  			"const defaultGOARM = `%s`\n"+
    73  			"const defaultGOOS = runtime.GOOS\n"+
    74  			"const defaultGOARCH = runtime.GOARCH\n"+
    75  			"const defaultGO_EXTLINK_ENABLED = `%s`\n"+
    76  			"const version = `%s`\n"+
    77  			"const stackGuardMultiplier = %d\n"+
    78  			"const goexperiment = `%s`\n",
    79  		goroot_final, go386, goarm, goextlinkenabled, findgoversion(), stackGuardMultiplier(), os.Getenv("GOEXPERIMENT"))
    80  
    81  	writefile(out, file, writeSkipSame)
    82  }
    83  
    84  // stackGuardMultiplier returns a multiplier to apply to the default
    85  // stack guard size. Larger multipliers are used for non-optimized
    86  // builds that have larger stack frames.
    87  func stackGuardMultiplier() int {
    88  	for _, s := range strings.Split(os.Getenv("GO_GCFLAGS"), " ") {
    89  		if s == "-N" {
    90  			return 2
    91  		}
    92  	}
    93  	return 1
    94  }