go scope_test 源码
golang scope_test 代码
文件路径：/src/cmd/compile/internal/dwarfgen/scope_test.go
// Copyright 2016 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 dwarfgen
import (
"debug/dwarf"
"fmt"
"internal/testenv"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"runtime"
"sort"
"strconv"
"strings"
"testing"
"cmd/internal/objfile"
)
type testline struct {
// line is one line of go source
line string
// scopes is a list of scope IDs of all the lexical scopes that this line
// of code belongs to.
// Scope IDs are assigned by traversing the tree of lexical blocks of a
// function in pre-order
// Scope IDs are function specific, i.e. scope 0 is always the root scope
// of the function that this line belongs to. Empty scopes are not assigned
// an ID (because they are not saved in debug_info).
// Scope 0 is always omitted from this list since all lines always belong
// to it.
scopes []int
// vars is the list of variables that belong in scopes[len(scopes)-1].
// Local variables are prefixed with "var ", formal parameters with "arg ".
// Must be ordered alphabetically.
// Set to nil to skip the check.
vars []string
// decl is the list of variables declared at this line.
decl []string
// declBefore is the list of variables declared at or before this line.
declBefore []string
}
var testfile = []testline{
{line: "package main"},
{line: "func f1(x int) { }"},
{line: "func f2(x int) { }"},
{line: "func f3(x int) { }"},
{line: "func f4(x int) { }"},
{line: "func f5(x int) { }"},
{line: "func f6(x int) { }"},
{line: "func fi(x interface{}) { if a, ok := x.(error); ok { a.Error() } }"},
{line: "func gret1() int { return 2 }"},
{line: "func gretbool() bool { return true }"},
{line: "func gret3() (int, int, int) { return 0, 1, 2 }"},
{line: "var v = []int{ 0, 1, 2 }"},
{line: "var ch = make(chan int)"},
{line: "var floatch = make(chan float64)"},
{line: "var iface interface{}"},
{line: "func TestNestedFor() {", vars: []string{"var a int"}},
{line: " a := 0", decl: []string{"a"}},
{line: " f1(a)"},
{line: " for i := 0; i < 5; i++ {", scopes: []int{1}, vars: []string{"var i int"}, decl: []string{"i"}},
{line: " f2(i)", scopes: []int{1}},
{line: " for i := 0; i < 5; i++ {", scopes: []int{1, 2}, vars: []string{"var i int"}, decl: []string{"i"}},
{line: " f3(i)", scopes: []int{1, 2}},
{line: " }"},
{line: " f4(i)", scopes: []int{1}},
{line: " }"},
{line: " f5(a)"},
{line: "}"},
{line: "func TestOas2() {", vars: []string{}},
{line: " if a, b, c := gret3(); a != 1 {", scopes: []int{1}, vars: []string{"var a int", "var b int", "var c int"}},
{line: " f1(a)", scopes: []int{1}},
{line: " f1(b)", scopes: []int{1}},
{line: " f1(c)", scopes: []int{1}},
{line: " }"},
{line: " for i, x := range v {", scopes: []int{2}, vars: []string{"var i int", "var x int"}},
{line: " f1(i)", scopes: []int{2}},
{line: " f1(x)", scopes: []int{2}},
{line: " }"},
{line: " if a, ok := <- ch; ok {", scopes: []int{3}, vars: []string{"var a int", "var ok bool"}},
{line: " f1(a)", scopes: []int{3}},
{line: " }"},
{line: " if a, ok := iface.(int); ok {", scopes: []int{4}, vars: []string{"var a int", "var ok bool"}},
{line: " f1(a)", scopes: []int{4}},
{line: " }"},
{line: "}"},
{line: "func TestIfElse() {"},
{line: " if x := gret1(); x != 0 {", scopes: []int{1}, vars: []string{"var x int"}},
{line: " a := 0", scopes: []int{1, 2}, vars: []string{"var a int"}},
{line: " f1(a); f1(x)", scopes: []int{1, 2}},
{line: " } else {"},
{line: " b := 1", scopes: []int{1, 3}, vars: []string{"var b int"}},
{line: " f1(b); f1(x+1)", scopes: []int{1, 3}},
{line: " }"},
{line: "}"},
{line: "func TestSwitch() {", vars: []string{}},
{line: " switch x := gret1(); x {", scopes: []int{1}, vars: []string{"var x int"}},
{line: " case 0:", scopes: []int{1, 2}},
{line: " i := x + 5", scopes: []int{1, 2}, vars: []string{"var i int"}},
{line: " f1(x); f1(i)", scopes: []int{1, 2}},
{line: " case 1:", scopes: []int{1, 3}},
{line: " j := x + 10", scopes: []int{1, 3}, vars: []string{"var j int"}},
{line: " f1(x); f1(j)", scopes: []int{1, 3}},
{line: " case 2:", scopes: []int{1, 4}},
{line: " k := x + 2", scopes: []int{1, 4}, vars: []string{"var k int"}},
{line: " f1(x); f1(k)", scopes: []int{1, 4}},
{line: " }"},
{line: "}"},
{line: "func TestTypeSwitch() {", vars: []string{}},
{line: " switch x := iface.(type) {"},
{line: " case int:", scopes: []int{1}},
{line: " f1(x)", scopes: []int{1}, vars: []string{"var x int"}},
{line: " case uint8:", scopes: []int{2}},
{line: " f1(int(x))", scopes: []int{2}, vars: []string{"var x uint8"}},
{line: " case float64:", scopes: []int{3}},
{line: " f1(int(x)+1)", scopes: []int{3}, vars: []string{"var x float64"}},
{line: " }"},
{line: "}"},
{line: "func TestSelectScope() {"},
{line: " select {"},
{line: " case i := <- ch:", scopes: []int{1}},
{line: " f1(i)", scopes: []int{1}, vars: []string{"var i int"}},
{line: " case f := <- floatch:", scopes: []int{2}},
{line: " f1(int(f))", scopes: []int{2}, vars: []string{"var f float64"}},
{line: " }"},
{line: "}"},
{line: "func TestBlock() {", vars: []string{"var a int"}},
{line: " a := 1"},
{line: " {"},
{line: " b := 2", scopes: []int{1}, vars: []string{"var b int"}},
{line: " f1(b)", scopes: []int{1}},
{line: " f1(a)", scopes: []int{1}},
{line: " }"},
{line: "}"},
{line: "func TestDiscontiguousRanges() {", vars: []string{"var a int"}},
{line: " a := 0"},
{line: " f1(a)"},
{line: " {"},
{line: " b := 0", scopes: []int{1}, vars: []string{"var b int"}},
{line: " f2(b)", scopes: []int{1}},
{line: " if gretbool() {", scopes: []int{1}},
{line: " c := 0", scopes: []int{1, 2}, vars: []string{"var c int"}},
{line: " f3(c)", scopes: []int{1, 2}},
{line: " } else {"},
{line: " c := 1.1", scopes: []int{1, 3}, vars: []string{"var c float64"}},
{line: " f4(int(c))", scopes: []int{1, 3}},
{line: " }"},
{line: " f5(b)", scopes: []int{1}},
{line: " }"},
{line: " f6(a)"},
{line: "}"},
{line: "func TestClosureScope() {", vars: []string{"var a int", "var b int", "var f func(int)"}},
{line: " a := 1; b := 1"},
{line: " f := func(c int) {", scopes: []int{0}, vars: []string{"arg c int", "var &b *int", "var a int", "var d int"}, declBefore: []string{"&b", "a"}},
{line: " d := 3"},
{line: " f1(c); f1(d)"},
{line: " if e := 3; e != 0 {", scopes: []int{1}, vars: []string{"var e int"}},
{line: " f1(e)", scopes: []int{1}},
{line: " f1(a)", scopes: []int{1}},
{line: " b = 2", scopes: []int{1}},
{line: " }"},
{line: " }"},
{line: " f(3); f1(b)"},
{line: "}"},
{line: "func TestEscape() {"},
{line: " a := 1", vars: []string{"var a int"}},
{line: " {"},
{line: " b := 2", scopes: []int{1}, vars: []string{"var &b *int", "var p *int"}},
{line: " p := &b", scopes: []int{1}},
{line: " f1(a)", scopes: []int{1}},
{line: " fi(p)", scopes: []int{1}},
{line: " }"},
{line: "}"},
{line: "var fglob func() int"},
{line: "func TestCaptureVar(flag bool) {"},
{line: " a := 1", vars: []string{"arg flag bool", "var a int"}}, // TODO(register args) restore "arg ~r1 func() int",
{line: " if flag {"},
{line: " b := 2", scopes: []int{1}, vars: []string{"var b int", "var f func() int"}},
{line: " f := func() int {", scopes: []int{1, 0}},
{line: " return b + 1"},
{line: " }"},
{line: " fglob = f", scopes: []int{1}},
{line: " }"},
{line: " f1(a)"},
{line: "}"},
{line: "func main() {"},
{line: " TestNestedFor()"},
{line: " TestOas2()"},
{line: " TestIfElse()"},
{line: " TestSwitch()"},
{line: " TestTypeSwitch()"},
{line: " TestSelectScope()"},
{line: " TestBlock()"},
{line: " TestDiscontiguousRanges()"},
{line: " TestClosureScope()"},
{line: " TestEscape()"},
{line: " TestCaptureVar(true)"},
{line: "}"},
}
const detailOutput = false
// Compiles testfile checks that the description of lexical blocks emitted
// by the linker in debug_info, for each function in the main package,
// corresponds to what we expect it to be.
func TestScopeRanges(t *testing.T) {
testenv.MustHaveGoBuild(t)
t.Parallel()
if runtime.GOOS == "plan9" {
t.Skip("skipping on plan9; no DWARF symbol table in executables")
}
dir, err := ioutil.TempDir("", "TestScopeRanges")
if err != nil {
t.Fatalf("could not create directory: %v", err)
}
defer os.RemoveAll(dir)
src, f := gobuild(t, dir, false, testfile)
defer f.Close()
// the compiler uses forward slashes for paths even on windows
src = strings.Replace(src, "\\", "/", -1)
pcln, err := f.PCLineTable()
if err != nil {
t.Fatal(err)
}
dwarfData, err := f.DWARF()
if err != nil {
t.Fatal(err)
}
dwarfReader := dwarfData.Reader()
lines := make(map[line][]*lexblock)
for {
entry, err := dwarfReader.Next()
if err != nil {
t.Fatal(err)
}
if entry == nil {
break
}
if entry.Tag != dwarf.TagSubprogram {
continue
}
name, ok := entry.Val(dwarf.AttrName).(string)
if !ok || !strings.HasPrefix(name, "main.Test") {
continue
}
var scope lexblock
ctxt := scopexplainContext{
dwarfData: dwarfData,
dwarfReader: dwarfReader,
scopegen: 1,
}
readScope(&ctxt, &scope, entry)
scope.markLines(pcln, lines)
}
anyerror := false
for i := range testfile {
tgt := testfile[i].scopes
out := lines[line{src, i + 1}]
if detailOutput {
t.Logf("%s // %v", testfile[i].line, out)
}
scopesok := checkScopes(tgt, out)
if !scopesok {
t.Logf("mismatch at line %d %q: expected: %v got: %v\n", i, testfile[i].line, tgt, scopesToString(out))
}
varsok := true
if testfile[i].vars != nil {
if len(out) > 0 {
varsok = checkVars(testfile[i].vars, out[len(out)-1].vars)
if !varsok {
t.Logf("variable mismatch at line %d %q for scope %d: expected: %v got: %v\n", i+1, testfile[i].line, out[len(out)-1].id, testfile[i].vars, out[len(out)-1].vars)
}
for j := range testfile[i].decl {
if line := declLineForVar(out[len(out)-1].vars, testfile[i].decl[j]); line != i+1 {
t.Errorf("wrong declaration line for variable %s, expected %d got: %d", testfile[i].decl[j], i+1, line)
}
}
for j := range testfile[i].declBefore {
if line := declLineForVar(out[len(out)-1].vars, testfile[i].declBefore[j]); line > i+1 {
t.Errorf("wrong declaration line for variable %s, expected %d (or less) got: %d", testfile[i].declBefore[j], i+1, line)
}
}
}
}
anyerror = anyerror || !scopesok || !varsok
}
if anyerror {
t.Fatalf("mismatched output")
}
}
func scopesToString(v []*lexblock) string {
r := make([]string, len(v))
for i, s := range v {
r[i] = strconv.Itoa(s.id)
}
return "[ " + strings.Join(r, ", ") + " ]"
}
func checkScopes(tgt []int, out []*lexblock) bool {
if len(out) > 0 {
// omit scope 0
out = out[1:]
}
if len(tgt) != len(out) {
return false
}
for i := range tgt {
if tgt[i] != out[i].id {
return false
}
}
return true
}
func checkVars(tgt []string, out []variable) bool {
if len(tgt) != len(out) {
return false
}
for i := range tgt {
if tgt[i] != out[i].expr {
return false
}
}
return true
}
func declLineForVar(scope []variable, name string) int {
for i := range scope {
if scope[i].name() == name {
return scope[i].declLine
}
}
return -1
}
type lexblock struct {
id int
ranges [][2]uint64
vars []variable
scopes []lexblock
}
type variable struct {
expr string
declLine int
}
func (v *variable) name() string {
return strings.Split(v.expr, " ")[1]
}
type line struct {
file string
lineno int
}
type scopexplainContext struct {
dwarfData *dwarf.Data
dwarfReader *dwarf.Reader
scopegen int
}
// readScope reads the DW_TAG_lexical_block or the DW_TAG_subprogram in
// entry and writes a description in scope.
// Nested DW_TAG_lexical_block entries are read recursively.
func readScope(ctxt *scopexplainContext, scope *lexblock, entry *dwarf.Entry) {
var err error
scope.ranges, err = ctxt.dwarfData.Ranges(entry)
if err != nil {
panic(err)
}
for {
e, err := ctxt.dwarfReader.Next()
if err != nil {
panic(err)
}
switch e.Tag {
case 0:
sort.Slice(scope.vars, func(i, j int) bool {
return scope.vars[i].expr < scope.vars[j].expr
})
return
case dwarf.TagFormalParameter:
typ, err := ctxt.dwarfData.Type(e.Val(dwarf.AttrType).(dwarf.Offset))
if err != nil {
panic(err)
}
scope.vars = append(scope.vars, entryToVar(e, "arg", typ))
case dwarf.TagVariable:
typ, err := ctxt.dwarfData.Type(e.Val(dwarf.AttrType).(dwarf.Offset))
if err != nil {
panic(err)
}
scope.vars = append(scope.vars, entryToVar(e, "var", typ))
case dwarf.TagLexDwarfBlock:
scope.scopes = append(scope.scopes, lexblock{id: ctxt.scopegen})
ctxt.scopegen++
readScope(ctxt, &scope.scopes[len(scope.scopes)-1], e)
}
}
}
func entryToVar(e *dwarf.Entry, kind string, typ dwarf.Type) variable {
return variable{
fmt.Sprintf("%s %s %s", kind, e.Val(dwarf.AttrName).(string), typ.String()),
int(e.Val(dwarf.AttrDeclLine).(int64)),
}
}
// markLines marks all lines that belong to this scope with this scope
// Recursively calls markLines for all children scopes.
func (scope *lexblock) markLines(pcln objfile.Liner, lines map[line][]*lexblock) {
for _, r := range scope.ranges {
for pc := r[0]; pc < r[1]; pc++ {
file, lineno, _ := pcln.PCToLine(pc)
l := line{file, lineno}
if len(lines[l]) == 0 || lines[l][len(lines[l])-1] != scope {
lines[l] = append(lines[l], scope)
}
}
}
for i := range scope.scopes {
scope.scopes[i].markLines(pcln, lines)
}
}
func gobuild(t *testing.T, dir string, optimized bool, testfile []testline) (string, *objfile.File) {
src := filepath.Join(dir, "test.go")
dst := filepath.Join(dir, "out.o")
f, err := os.Create(src)
if err != nil {
t.Fatal(err)
}
for i := range testfile {
f.Write([]byte(testfile[i].line))
f.Write([]byte{'\n'})
}
f.Close()
args := []string{"build"}
if !optimized {
args = append(args, "-gcflags=-N -l")
}
args = append(args, "-o", dst, src)
cmd := exec.Command(testenv.GoToolPath(t), args...)
if b, err := cmd.CombinedOutput(); err != nil {
t.Logf("build: %s\n", string(b))
t.Fatal(err)
}
pkg, err := objfile.Open(dst)
if err != nil {
t.Fatal(err)
}
return src, pkg
}
// TestEmptyDwarfRanges tests that no list entry in debug_ranges has start == end.
// See issue #23928.
func TestEmptyDwarfRanges(t *testing.T) {
testenv.MustHaveGoRun(t)
t.Parallel()
if runtime.GOOS == "plan9" {
t.Skip("skipping on plan9; no DWARF symbol table in executables")
}
dir, err := ioutil.TempDir("", "TestEmptyDwarfRanges")
if err != nil {
t.Fatalf("could not create directory: %v", err)
}
defer os.RemoveAll(dir)
_, f := gobuild(t, dir, true, []testline{{line: "package main"}, {line: "func main(){ println(\"hello\") }"}})
defer f.Close()
dwarfData, err := f.DWARF()
if err != nil {
t.Fatal(err)
}
dwarfReader := dwarfData.Reader()
for {
entry, err := dwarfReader.Next()
if err != nil {
t.Fatal(err)
}
if entry == nil {
break
}
ranges, err := dwarfData.Ranges(entry)
if err != nil {
t.Fatal(err)
}
if ranges == nil {
continue
}
for _, rng := range ranges {
if rng[0] == rng[1] {
t.Errorf("range entry with start == end: %v", rng)
}
}
}
}
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