src/cmd/compile/internal/test/pgo_devirtualize_test.go

   1 // Copyright 2023 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 test
   6
   7 import (
   8         "bufio"
   9         "fmt"
  10         "internal/testenv"
  11         "os"
  12         "path/filepath"
  13         "regexp"
  14         "testing"
  15 )
  16
  17 // testPGODevirtualize tests that specific PGO devirtualize rewrites are performed.
  18 func testPGODevirtualize(t *testing.T, dir string) {
  19         testenv.MustHaveGoRun(t)
  20         t.Parallel()
  21
  22         const pkg = "example.com/pgo/devirtualize"
  23
  24         // Add a go.mod so we have a consistent symbol names in this temp dir.
  25         goMod := fmt.Sprintf(`module %s
  26 go 1.19
  27 `, pkg)
  28         if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte(goMod), 0644); err != nil {
  29                 t.Fatalf("error writing go.mod: %v", err)
  30         }
  31
  32         // Run the test without PGO to ensure that the test assertions are
  33         // correct even in the non-optimized version.
  34         cmd := testenv.CleanCmdEnv(testenv.Command(t, testenv.GoToolPath(t), "test", "."))
  35         cmd.Dir = dir
  36         b, err := cmd.CombinedOutput()
  37         t.Logf("Test without PGO:\n%s", b)
  38         if err != nil {
  39                 t.Fatalf("Test failed without PGO: %v", err)
  40         }
  41
  42         // Build the test with the profile.
  43         pprof := filepath.Join(dir, "devirt.pprof")
  44         gcflag := fmt.Sprintf("-gcflags=-m=2 -pgoprofile=%s -d=pgodebug=3", pprof)
  45         out := filepath.Join(dir, "test.exe")
  46         cmd = testenv.CleanCmdEnv(testenv.Command(t, testenv.GoToolPath(t), "test", "-o", out, gcflag, "."))
  47         cmd.Dir = dir
  48
  49         pr, pw, err := os.Pipe()
  50         if err != nil {
  51                 t.Fatalf("error creating pipe: %v", err)
  52         }
  53         defer pr.Close()
  54         cmd.Stdout = pw
  55         cmd.Stderr = pw
  56
  57         err = cmd.Start()
  58         pw.Close()
  59         if err != nil {
  60                 t.Fatalf("error starting go test: %v", err)
  61         }
  62
  63         type devirtualization struct {
  64                 pos    string
  65                 callee string
  66         }
  67
  68         want := []devirtualization{
  69                 // ExerciseIface
  70                 {
  71                         pos:    "./devirt.go:101:20",
  72                         callee: "mult.Mult.Multiply",
  73                 },
  74                 {
  75                         pos:    "./devirt.go:101:39",
  76                         callee: "Add.Add",
  77                 },
  78                 // ExerciseFuncConcrete
  79                 {
  80                         pos:    "./devirt.go:173:36",
  81                         callee: "AddFn",
  82                 },
  83                 {
  84                         pos:    "./devirt.go:173:15",
  85                         callee: "mult.MultFn",
  86                 },
  87                 // ExerciseFuncField
  88                 {
  89                         pos:    "./devirt.go:207:35",
  90                         callee: "AddFn",
  91                 },
  92                 {
  93                         pos:    "./devirt.go:207:19",
  94                         callee: "mult.MultFn",
  95                 },
  96                 // ExerciseFuncClosure
  97                 // TODO(prattmic): Closure callees not implemented.
  98                 //{
  99                 //      pos:    "./devirt.go:249:27",
 100                 //      callee: "AddClosure.func1",
 101                 //},
 102                 //{
 103                 //      pos:    "./devirt.go:249:15",
 104                 //      callee: "mult.MultClosure.func1",
 105                 //},
 106         }
 107
 108         got := make(map[devirtualization]struct{})
 109
 110         devirtualizedLine := regexp.MustCompile(`(.*): PGO devirtualizing \w+ call .* to (.*)`)
 111
 112         scanner := bufio.NewScanner(pr)
 113         for scanner.Scan() {
 114                 line := scanner.Text()
 115                 t.Logf("child: %s", line)
 116
 117                 m := devirtualizedLine.FindStringSubmatch(line)
 118                 if m == nil {
 119                         continue
 120                 }
 121
 122                 d := devirtualization{
 123                         pos:    m[1],
 124                         callee: m[2],
 125                 }
 126                 got[d] = struct{}{}
 127         }
 128         if err := cmd.Wait(); err != nil {
 129                 t.Fatalf("error running go test: %v", err)
 130         }
 131         if err := scanner.Err(); err != nil {
 132                 t.Fatalf("error reading go test output: %v", err)
 133         }
 134
 135         if len(got) != len(want) {
 136                 t.Errorf("mismatched devirtualization count; got %v want %v", got, want)
 137         }
 138         for _, w := range want {
 139                 if _, ok := got[w]; ok {
 140                         continue
 141                 }
 142                 t.Errorf("devirtualization %v missing; got %v", w, got)
 143         }
 144
 145         // Run test with PGO to ensure the assertions are still true.
 146         cmd = testenv.CleanCmdEnv(testenv.Command(t, out))
 147         cmd.Dir = dir
 148         b, err = cmd.CombinedOutput()
 149         t.Logf("Test with PGO:\n%s", b)
 150         if err != nil {
 151                 t.Fatalf("Test failed without PGO: %v", err)
 152         }
 153 }
 154
 155 // TestPGODevirtualize tests that specific functions are devirtualized when PGO
 156 // is applied to the exact source that was profiled.
 157 func TestPGODevirtualize(t *testing.T) {
 158         wd, err := os.Getwd()
 159         if err != nil {
 160                 t.Fatalf("error getting wd: %v", err)
 161         }
 162         srcDir := filepath.Join(wd, "testdata", "pgo", "devirtualize")
 163
 164         // Copy the module to a scratch location so we can add a go.mod.
 165         dir := t.TempDir()
 166         if err := os.Mkdir(filepath.Join(dir, "mult.pkg"), 0755); err != nil {
 167                 t.Fatalf("error creating dir: %v", err)
 168         }
 169         for _, file := range []string{"devirt.go", "devirt_test.go", "devirt.pprof", filepath.Join("mult.pkg", "mult.go")} {
 170                 if err := copyFile(filepath.Join(dir, file), filepath.Join(srcDir, file)); err != nil {
 171                         t.Fatalf("error copying %s: %v", file, err)
 172                 }
 173         }
 174
 175         testPGODevirtualize(t, dir)
 176 }