--- /dev/null
+// Copyright 2021 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 noder_test
+
+import (
+ "encoding/json"
+ "flag"
+ exec "internal/execabs"
+ "os"
+ "reflect"
+ "runtime"
+ "strings"
+ "testing"
+)
+
+var (
+ flagPkgs = flag.String("pkgs", "std", "list of packages to compare")
+ flagAll = flag.Bool("all", false, "enable testing of all GOOS/GOARCH targets")
+ flagParallel = flag.Bool("parallel", false, "test GOOS/GOARCH targets in parallel")
+)
+
+// TestUnifiedCompare implements a test similar to running:
+//
+// $ go build -toolexec="toolstash -cmp" std
+//
+// The -pkgs flag controls the list of packages tested.
+//
+// By default, only the native GOOS/GOARCH target is enabled. The -all
+// flag enables testing of non-native targets. The -parallel flag
+// additionally enables testing of targets in parallel.
+//
+// Caution: Testing all targets is very resource intensive! On an IBM
+// P920 (dual Intel Xeon Gold 6154 CPUs; 36 cores, 192GB RAM), testing
+// all targets in parallel takes about 5 minutes. Using the 'go test'
+// command's -run flag for subtest matching is recommended for less
+// powerful machines.
+func TestUnifiedCompare(t *testing.T) {
+ if testing.Short() {
+ t.Skip("skipping test in short mode")
+ }
+
+ targets, err := exec.Command("go", "tool", "dist", "list").Output()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ for _, target := range strings.Fields(string(targets)) {
+ t.Run(target, func(t *testing.T) {
+ parts := strings.Split(target, "/")
+ goos, goarch := parts[0], parts[1]
+
+ if !(*flagAll || goos == runtime.GOOS && goarch == runtime.GOARCH) {
+ t.Skip("skipping non-native target (use -all to enable)")
+ }
+ if *flagParallel {
+ t.Parallel()
+ }
+
+ pkgs1 := loadPackages(t, goos, goarch, "-d=unified=0 -d=inlfuncswithclosures=0")
+ pkgs2 := loadPackages(t, goos, goarch, "-d=unified=1 -d=inlfuncswithclosures=0")
+
+ if len(pkgs1) != len(pkgs2) {
+ t.Fatalf("length mismatch: %v != %v", len(pkgs1), len(pkgs2))
+ }
+
+ for i := range pkgs1 {
+ pkg1 := pkgs1[i]
+ pkg2 := pkgs2[i]
+
+ path := pkg1.ImportPath
+ if path != pkg2.ImportPath {
+ t.Fatalf("mismatched paths: %q != %q", path, pkg2.ImportPath)
+ }
+
+ // Packages that don't have any source files (e.g., packages
+ // unsafe, embed/internal/embedtest, and cmd/internal/moddeps).
+ if pkg1.Export == "" && pkg2.Export == "" {
+ continue
+ }
+
+ if pkg1.BuildID == pkg2.BuildID {
+ t.Errorf("package %q: build IDs unexpectedly matched", path)
+ }
+
+ // Unlike toolstash -cmp, we're comparing the same compiler
+ // binary against itself, just with different flags. So we
+ // don't need to worry about skipping over mismatched version
+ // strings, but we do need to account for differing build IDs.
+ //
+ // Fortunately, build IDs are cryptographic 256-bit hashes,
+ // and cmd/go provides us with them up front. So we can just
+ // use them as delimeters to split the files, and then check
+ // that the substrings are all equal.
+ file1 := strings.Split(readFile(t, pkg1.Export), pkg1.BuildID)
+ file2 := strings.Split(readFile(t, pkg2.Export), pkg2.BuildID)
+ if !reflect.DeepEqual(file1, file2) {
+ t.Errorf("package %q: compile output differs", path)
+ }
+ }
+ })
+ }
+}
+
+type pkg struct {
+ ImportPath string
+ Export string
+ BuildID string
+ Incomplete bool
+}
+
+func loadPackages(t *testing.T, goos, goarch, gcflags string) []pkg {
+ args := []string{"list", "-e", "-export", "-json", "-gcflags=all=" + gcflags, "--"}
+ args = append(args, strings.Fields(*flagPkgs)...)
+
+ cmd := exec.Command("go", args...)
+ cmd.Env = append(os.Environ(), "GOOS="+goos, "GOARCH="+goarch)
+ cmd.Stderr = os.Stderr
+ stdout, err := cmd.StdoutPipe()
+ if err != nil {
+ t.Fatal(err)
+ }
+ if err := cmd.Start(); err != nil {
+ t.Fatal(err)
+ }
+
+ var res []pkg
+ for dec := json.NewDecoder(stdout); dec.More(); {
+ var pkg pkg
+ if err := dec.Decode(&pkg); err != nil {
+ t.Fatal(err)
+ }
+ if pkg.Incomplete {
+ t.Fatalf("incomplete package: %q", pkg.ImportPath)
+ }
+ res = append(res, pkg)
+ }
+ if err := cmd.Wait(); err != nil {
+ t.Fatal(err)
+ }
+ return res
+}
+
+func readFile(t *testing.T, name string) string {
+ buf, err := os.ReadFile(name)
+ if err != nil {
+ t.Fatal(err)
+ }
+ return string(buf)
+}