cmd/dist: reproducibility fixes

Fix a few lingering reproducibility problems.

- Do not set CC during go install std if it is unset,
  so that the automatic disabling of cgo in cmd/go can run.

- Since CC is not necessary, remove code insisting on it.

- Use a fixed quoting algorithm instead of %q from the
  bootstrap toolchain, which can differ from release to release.

- Remove go_bootstrap tool successfully on Windows.

For #24904.

Change-Id: I5c29ba6a8592e93bfab37f123b69f55c02f12ce3
Reviewed-on: https://go-review.googlesource.com/c/go/+/475377
Auto-Submit: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 1c63c6ebc7b182fdd11b453993f12986b6bf278c..343f0ce332f82b4db2deb90f19b6a33b44f5e2b2 100644 (file)
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -313,6 +313,9 @@ var clangos = []string{
 // compilerEnvLookup returns the compiler settings for goos/goarch in map m.
 // kind is "CC" or "CXX".
 func compilerEnvLookup(kind string, m map[string]string, goos, goarch string) string {
+       if !needCC() {
+               return ""
+       }
        if cc := m[goos+"/"+goarch]; cc != "" {
                return cc
        }
@@ -1568,7 +1571,7 @@ func cmdbootstrap() {
        }
 
        // Remove go_bootstrap now that we're done.
-       xremove(pathf("%s/go_bootstrap", tooldir))
+       xremove(pathf("%s/go_bootstrap"+exe, tooldir))
 
        if goos == "android" {
                // Make sure the exec wrapper will sync a fresh $GOROOT to the device.
@@ -1740,13 +1743,7 @@ var firstClass = map[string]bool{
 }
 
 func needCC() bool {
-       switch os.Getenv("CGO_ENABLED") {
-       case "1":
-               return true
-       case "0":
-               return false
-       }
-       return cgoEnabled[gohostos+"/"+gohostarch]
+       return os.Getenv("CGO_ENABLED") == "1"
 }
 
 func checkCC() {

diff --git a/src/cmd/dist/buildgo.go b/src/cmd/dist/buildgo.go
index 7f1bc0105e061a2bd7b8749b3ef9e62c4bddb913..d6a3b8121435e2695769af3252d7edd76720bf79 100644 (file)
--- a/src/cmd/dist/buildgo.go
+++ b/src/cmd/dist/buildgo.go
@@ -63,11 +63,11 @@ func defaultCCFunc(name string, defaultcc map[string]string) string {
        }
        sort.Strings(keys)
        for _, k := range keys {
-               fmt.Fprintf(&buf, "\tcase %q:\n\t\treturn %q\n", k, defaultcc[k])
+               fmt.Fprintf(&buf, "\tcase %s:\n\t\treturn %s\n", quote(k), quote(defaultcc[k]))
        }
        fmt.Fprintf(&buf, "\t}\n")
        if cc := defaultcc[""]; cc != "" {
-               fmt.Fprintf(&buf, "\treturn %q\n", cc)
+               fmt.Fprintf(&buf, "\treturn %s\n", quote(cc))
        } else {
                clang, gcc := "clang", "gcc"
                if strings.HasSuffix(name, "CXX") {
@@ -79,12 +79,12 @@ func defaultCCFunc(name string, defaultcc map[string]string) string {
                        if i > 0 {
                                fmt.Fprintf(&buf, ", ")
                        }
-                       fmt.Fprintf(&buf, "%q", os)
+                       fmt.Fprintf(&buf, "%s", quote(os))
                }
                fmt.Fprintf(&buf, ":\n")
-               fmt.Fprintf(&buf, "\t\treturn %q\n", clang)
+               fmt.Fprintf(&buf, "\t\treturn %s\n", quote(clang))
                fmt.Fprintf(&buf, "\t}\n")
-               fmt.Fprintf(&buf, "\treturn %q\n", gcc)
+               fmt.Fprintf(&buf, "\treturn %s\n", quote(gcc))
        }
        fmt.Fprintf(&buf, "}\n")
 
@@ -105,7 +105,7 @@ func mkzosarch(dir, file string) {
        fmt.Fprintf(&buf, "package cfg\n\n")
        fmt.Fprintf(&buf, "var OSArchSupportsCgo = map[string]bool{\n")
        for _, plat := range list {
-               fmt.Fprintf(&buf, "\t%q: %v,\n", plat, cgoEnabled[plat])
+               fmt.Fprintf(&buf, "\t%s: %v,\n", quote(plat), cgoEnabled[plat])
        }
        fmt.Fprintf(&buf, "}\n")
 
@@ -133,11 +133,11 @@ func mkzcgo(dir, file string) {
        fmt.Fprintln(&buf)
        fmt.Fprintf(&buf, "package build\n")
        fmt.Fprintln(&buf)
-       fmt.Fprintf(&buf, "const defaultCGO_ENABLED = %q\n", os.Getenv("CGO_ENABLED"))
+       fmt.Fprintf(&buf, "const defaultCGO_ENABLED = %s\n", quote(os.Getenv("CGO_ENABLED")))
        fmt.Fprintln(&buf)
        fmt.Fprintf(&buf, "var cgoEnabled = map[string]bool{\n")
        for _, plat := range list {
-               fmt.Fprintf(&buf, "\t%q: true,\n", plat)
+               fmt.Fprintf(&buf, "\t%s: true,\n", quote(plat))
        }
        fmt.Fprintf(&buf, "}\n")
 
@@ -156,7 +156,28 @@ func mktzdata(dir, file string) {
        fmt.Fprintln(&buf)
        fmt.Fprintf(&buf, "package tzdata\n")
        fmt.Fprintln(&buf)
-       fmt.Fprintf(&buf, "const zipdata = %q\n", zip)
+       fmt.Fprintf(&buf, "const zipdata = %s\n", quote(zip))
 
        writefile(buf.String(), file, writeSkipSame)
 }
+
+// quote is like strconv.Quote but simpler and has output
+// that does not depend on the exact Go bootstrap version.
+func quote(s string) string {
+       const hex = "0123456789abcdef"
+       var out strings.Builder
+       out.WriteByte('"')
+       for i := 0; i < len(s); i++ {
+               c := s[i]
+               if 0x20 <= c && c <= 0x7E && c != '"' && c != '\\' {
+                       out.WriteByte(c)
+               } else {
+                       out.WriteByte('\\')
+                       out.WriteByte('x')
+                       out.WriteByte(hex[c>>4])
+                       out.WriteByte(hex[c&0xf])
+               }
+       }
+       out.WriteByte('"')
+       return out.String()
+}