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// Copyright 2023 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 test
import (
"bufio"
"fmt"
"internal/testenv"
"os"
"path/filepath"
"regexp"
"testing"
)
type devirtualization struct {
pos string
callee string
}
const profFileName = "devirt.pprof"
const preProfFileName = "devirt.pprof.node_map"
// testPGODevirtualize tests that specific PGO devirtualize rewrites are performed.
func testPGODevirtualize(t *testing.T, dir string, want []devirtualization, pgoProfileName string) {
testenv.MustHaveGoRun(t)
t.Parallel()
const pkg = "example.com/pgo/devirtualize"
// Add a go.mod so we have a consistent symbol names in this temp dir.
goMod := fmt.Sprintf(`module %s
go 1.21
`, pkg)
if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte(goMod), 0644); err != nil {
t.Fatalf("error writing go.mod: %v", err)
}
// Run the test without PGO to ensure that the test assertions are
// correct even in the non-optimized version.
cmd := testenv.CleanCmdEnv(testenv.Command(t, testenv.GoToolPath(t), "test", "."))
cmd.Dir = dir
b, err := cmd.CombinedOutput()
t.Logf("Test without PGO:\n%s", b)
if err != nil {
t.Fatalf("Test failed without PGO: %v", err)
}
// Build the test with the profile.
pprof := filepath.Join(dir, pgoProfileName)
gcflag := fmt.Sprintf("-gcflags=-m=2 -pgoprofile=%s -d=pgodebug=3", pprof)
out := filepath.Join(dir, "test.exe")
cmd = testenv.CleanCmdEnv(testenv.Command(t, testenv.GoToolPath(t), "test", "-o", out, gcflag, "."))
cmd.Dir = dir
pr, pw, err := os.Pipe()
if err != nil {
t.Fatalf("error creating pipe: %v", err)
}
defer pr.Close()
cmd.Stdout = pw
cmd.Stderr = pw
err = cmd.Start()
pw.Close()
if err != nil {
t.Fatalf("error starting go test: %v", err)
}
got := make(map[devirtualization]struct{})
devirtualizedLine := regexp.MustCompile(`(.*): PGO devirtualizing \w+ call .* to (.*)`)
scanner := bufio.NewScanner(pr)
for scanner.Scan() {
line := scanner.Text()
t.Logf("child: %s", line)
m := devirtualizedLine.FindStringSubmatch(line)
if m == nil {
continue
}
d := devirtualization{
pos: m[1],
callee: m[2],
}
got[d] = struct{}{}
}
if err := cmd.Wait(); err != nil {
t.Fatalf("error running go test: %v", err)
}
if err := scanner.Err(); err != nil {
t.Fatalf("error reading go test output: %v", err)
}
if len(got) != len(want) {
t.Errorf("mismatched devirtualization count; got %v want %v", got, want)
}
for _, w := range want {
if _, ok := got[w]; ok {
continue
}
t.Errorf("devirtualization %v missing; got %v", w, got)
}
// Run test with PGO to ensure the assertions are still true.
cmd = testenv.CleanCmdEnv(testenv.Command(t, out))
cmd.Dir = dir
b, err = cmd.CombinedOutput()
t.Logf("Test with PGO:\n%s", b)
if err != nil {
t.Fatalf("Test failed without PGO: %v", err)
}
}
// TestPGODevirtualize tests that specific functions are devirtualized when PGO
// is applied to the exact source that was profiled.
func TestPGODevirtualize(t *testing.T) {
wd, err := os.Getwd()
if err != nil {
t.Fatalf("error getting wd: %v", err)
}
srcDir := filepath.Join(wd, "testdata", "pgo", "devirtualize")
// Copy the module to a scratch location so we can add a go.mod.
dir := t.TempDir()
if err := os.Mkdir(filepath.Join(dir, "mult.pkg"), 0755); err != nil {
t.Fatalf("error creating dir: %v", err)
}
for _, file := range []string{"devirt.go", "devirt_test.go", profFileName, filepath.Join("mult.pkg", "mult.go")} {
if err := copyFile(filepath.Join(dir, file), filepath.Join(srcDir, file)); err != nil {
t.Fatalf("error copying %s: %v", file, err)
}
}
want := []devirtualization{
// ExerciseIface
{
pos: "./devirt.go:101:20",
callee: "mult.Mult.Multiply",
},
{
pos: "./devirt.go:101:39",
callee: "Add.Add",
},
// ExerciseFuncConcrete
{
pos: "./devirt.go:173:36",
callee: "AddFn",
},
{
pos: "./devirt.go:173:15",
callee: "mult.MultFn",
},
// ExerciseFuncField
{
pos: "./devirt.go:207:35",
callee: "AddFn",
},
{
pos: "./devirt.go:207:19",
callee: "mult.MultFn",
},
// ExerciseFuncClosure
// TODO(prattmic): Closure callees not implemented.
//{
// pos: "./devirt.go:249:27",
// callee: "AddClosure.func1",
//},
//{
// pos: "./devirt.go:249:15",
// callee: "mult.MultClosure.func1",
//},
}
testPGODevirtualize(t, dir, want, profFileName)
}
// TestPGOPreprocessDevirtualize tests that specific functions are devirtualized when PGO
// is applied to the exact source that was profiled. The input profile is PGO preprocessed file.
func TestPGOPreprocessDevirtualize(t *testing.T) {
wd, err := os.Getwd()
if err != nil {
t.Fatalf("error getting wd: %v", err)
}
srcDir := filepath.Join(wd, "testdata", "pgo", "devirtualize")
// Copy the module to a scratch location so we can add a go.mod.
dir := t.TempDir()
if err := os.Mkdir(filepath.Join(dir, "mult.pkg"), 0755); err != nil {
t.Fatalf("error creating dir: %v", err)
}
for _, file := range []string{"devirt.go", "devirt_test.go", preProfFileName, filepath.Join("mult.pkg", "mult.go")} {
if err := copyFile(filepath.Join(dir, file), filepath.Join(srcDir, file)); err != nil {
t.Fatalf("error copying %s: %v", file, err)
}
}
want := []devirtualization{
// ExerciseIface
{
pos: "./devirt.go:101:20",
callee: "mult.Mult.Multiply",
},
{
pos: "./devirt.go:101:39",
callee: "Add.Add",
},
// ExerciseFuncConcrete
{
pos: "./devirt.go:173:36",
callee: "AddFn",
},
{
pos: "./devirt.go:173:15",
callee: "mult.MultFn",
},
// ExerciseFuncField
{
pos: "./devirt.go:207:35",
callee: "AddFn",
},
{
pos: "./devirt.go:207:19",
callee: "mult.MultFn",
},
// ExerciseFuncClosure
// TODO(prattmic): Closure callees not implemented.
//{
// pos: "./devirt.go:249:27",
// callee: "AddClosure.func1",
//},
//{
// pos: "./devirt.go:249:15",
// callee: "mult.MultClosure.func1",
//},
}
testPGODevirtualize(t, dir, want, preProfFileName)
}
// Regression test for https://go.dev/issue/65615. If a target function changes
// from non-generic to generic we can't devirtualize it (don't know the type
// parameters), but the compiler should not crash.
func TestLookupFuncGeneric(t *testing.T) {
wd, err := os.Getwd()
if err != nil {
t.Fatalf("error getting wd: %v", err)
}
srcDir := filepath.Join(wd, "testdata", "pgo", "devirtualize")
// Copy the module to a scratch location so we can add a go.mod.
dir := t.TempDir()
if err := os.Mkdir(filepath.Join(dir, "mult.pkg"), 0755); err != nil {
t.Fatalf("error creating dir: %v", err)
}
for _, file := range []string{"devirt.go", "devirt_test.go", profFileName, filepath.Join("mult.pkg", "mult.go")} {
if err := copyFile(filepath.Join(dir, file), filepath.Join(srcDir, file)); err != nil {
t.Fatalf("error copying %s: %v", file, err)
}
}
// Change MultFn from a concrete function to a parameterized function.
if err := convertMultToGeneric(filepath.Join(dir, "mult.pkg", "mult.go")); err != nil {
t.Fatalf("error editing mult.go: %v", err)
}
// Same as TestPGODevirtualize except for MultFn, which we cannot
// devirtualize to because it has become generic.
//
// Note that the important part of this test is that the build is
// successful, not the specific devirtualizations.
want := []devirtualization{
// ExerciseIface
{
pos: "./devirt.go:101:20",
callee: "mult.Mult.Multiply",
},
{
pos: "./devirt.go:101:39",
callee: "Add.Add",
},
// ExerciseFuncConcrete
{
pos: "./devirt.go:173:36",
callee: "AddFn",
},
// ExerciseFuncField
{
pos: "./devirt.go:207:35",
callee: "AddFn",
},
// ExerciseFuncClosure
// TODO(prattmic): Closure callees not implemented.
//{
// pos: "./devirt.go:249:27",
// callee: "AddClosure.func1",
//},
//{
// pos: "./devirt.go:249:15",
// callee: "mult.MultClosure.func1",
//},
}
testPGODevirtualize(t, dir, want, profFileName)
}
var multFnRe = regexp.MustCompile(`func MultFn\(a, b int64\) int64`)
func convertMultToGeneric(path string) error {
content, err := os.ReadFile(path)
if err != nil {
return fmt.Errorf("error opening: %w", err)
}
if !multFnRe.Match(content) {
return fmt.Errorf("MultFn not found; update regexp?")
}
// Users of MultFn shouldn't need adjustment, type inference should
// work OK.
content = multFnRe.ReplaceAll(content, []byte(`func MultFn[T int32|int64](a, b T) T`))
return os.WriteFile(path, content, 0644)
}