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|
package main
import (
"bufio"
"fmt"
"go/build/constraint"
"log"
"os"
"path/filepath"
"regexp"
"sort"
"strings"
)
var goVersionRegex = regexp.MustCompile(`^go1.(\d+)$`)
// Used to update the list of tags affecting the standard library kept in
// transitions.bzl.
func main() {
if len(os.Args) < 2 {
log.Fatal("usage: stdlib_tags <go SDK src directory>...")
}
filteredTags, err := extractBuildTags(os.Args[1:]...)
if err != nil {
log.Fatal(err.Error())
}
fmt.Printf("_TAG_AFFECTS_STDLIB = {\n")
for _, tag := range filteredTags {
fmt.Printf(" %q: None,\n", tag)
}
fmt.Printf("}\n")
}
func extractBuildTags(sdkPaths ...string) ([]string, error) {
tags := make(map[string]struct{})
for _, dir := range sdkPaths {
err := filepath.WalkDir(dir, func(path string, d os.DirEntry, err error) error {
if d.IsDir() {
if d.Name() == "testdata" {
return filepath.SkipDir
}
return nil
}
if filepath.Ext(path) != ".go" {
return nil
}
if strings.HasSuffix(filepath.Base(path), "_test.go") {
return nil
}
return walkFile(path, tags)
})
if err != nil {
return nil, fmt.Errorf("%s: %w", dir, err)
}
}
filteredTags := make([]string, 0, len(tags))
for tag := range tags {
if !shouldExclude(tag) {
filteredTags = append(filteredTags, tag)
}
}
sort.Strings(filteredTags)
return filteredTags, nil
}
func shouldExclude(tag string) bool {
// Set via CGO_ENABLED
return tag == "cgo" ||
// Set via GOARCH and GOOS
knownOS[tag] || knownArch[tag] || tag == "unix" ||
// Set via GOEXPERIMENT and GOAMD64
strings.HasPrefix(tag, "goexperiment.") || strings.HasPrefix(tag, "amd64.") ||
// Set implicitly
goVersionRegex.MatchString(tag)
}
func walkFile(path string, tags map[string]struct{}) error {
file, err := os.Open(path)
if err != nil {
return err
}
scanner := bufio.NewScanner(file)
// The Go SDK contains some very long lines in vendored files (minified JS).
scanner.Buffer(make([]byte, 0, 128*1024), 1024*1024)
for scanner.Scan() {
line := scanner.Text()
if !isConstraint(line) {
continue
}
c, err := constraint.Parse(line)
if err != nil {
continue
}
walkConstraint(c, tags)
}
if err = scanner.Err(); err != nil {
return fmt.Errorf("%s: %w", path, err)
}
return nil
}
func walkConstraint(c constraint.Expr, tags map[string]struct{}) {
switch c.(type) {
case *constraint.AndExpr:
walkConstraint(c.(*constraint.AndExpr).X, tags)
walkConstraint(c.(*constraint.AndExpr).Y, tags)
case *constraint.OrExpr:
walkConstraint(c.(*constraint.OrExpr).X, tags)
walkConstraint(c.(*constraint.OrExpr).Y, tags)
case *constraint.NotExpr:
walkConstraint(c.(*constraint.NotExpr).X, tags)
case *constraint.TagExpr:
tags[c.(*constraint.TagExpr).Tag] = struct{}{}
}
}
func isConstraint(line string) bool {
return constraint.IsPlusBuild(line) || constraint.IsGoBuild(line)
}
// Taken from
// https://github.com/golang/go/blob/3d5391ed87d813110e10b954c62bf7ed578b591f/src/go/build/syslist.go
var knownOS = map[string]bool{
"aix": true,
"android": true,
"darwin": true,
"dragonfly": true,
"freebsd": true,
"hurd": true,
"illumos": true,
"ios": true,
"js": true,
"linux": true,
"nacl": true,
"netbsd": true,
"openbsd": true,
"plan9": true,
"solaris": true,
"windows": true,
"zos": true,
}
var knownArch = map[string]bool{
"386": true,
"amd64": true,
"amd64p32": true,
"arm": true,
"armbe": true,
"arm64": true,
"arm64be": true,
"loong64": true,
"mips": true,
"mipsle": true,
"mips64": true,
"mips64le": true,
"mips64p32": true,
"mips64p32le": true,
"ppc": true,
"ppc64": true,
"ppc64le": true,
"riscv": true,
"riscv64": true,
"s390": true,
"s390x": true,
"sparc": true,
"sparc64": true,
"wasm": true,
}
|
