|
- // Copyright 2018 Google Inc. All Rights Reserved.
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- package dwarf_test
-
- import (
- "fmt"
- "io/ioutil"
- "os"
- "os/exec"
- "path/filepath"
- "runtime"
- "strings"
- "testing"
-
- "cloud.google.com/go/cmd/go-cloud-debug-agent/internal/debug/dwarf"
- "cloud.google.com/go/cmd/go-cloud-debug-agent/internal/debug/elf"
- )
-
- var (
- pcspTempDir string
- pcsptestBinary string
- )
-
- func doPCToSPTest(self bool) bool {
- // For now, only works on amd64 platforms.
- if runtime.GOARCH != "amd64" {
- return false
- }
- // Self test reads test binary; only works on Linux or Mac.
- if self {
- if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
- return false
- }
- }
- // Command below expects "sh", so Unix.
- if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
- return false
- }
- if pcsptestBinary != "" {
- return true
- }
- var err error
- pcspTempDir, err = ioutil.TempDir("", "pcsptest")
- if err != nil {
- panic(err)
- }
- if strings.Contains(pcspTempDir, " ") {
- panic("unexpected space in tempdir")
- }
- // This command builds pcsptest from testdata/pcsptest.go.
- pcsptestBinary = filepath.Join(pcspTempDir, "pcsptest")
- command := fmt.Sprintf("go tool compile -o %s.6 testdata/pcsptest.go && go tool link -H %s -o %s %s.6",
- pcsptestBinary, runtime.GOOS, pcsptestBinary, pcsptestBinary)
- cmd := exec.Command("sh", "-c", command)
- cmd.Stdout = os.Stdout
- cmd.Stderr = os.Stderr
- if err := cmd.Run(); err != nil {
- panic(err)
- }
- return true
- }
-
- func endPCToSPTest() {
- if pcspTempDir != "" {
- os.RemoveAll(pcspTempDir)
- pcspTempDir = ""
- pcsptestBinary = ""
- }
- }
-
- func TestPCToSPOffset(t *testing.T) {
- t.Skip("gets a stack layout it doesn't expect")
-
- if !doPCToSPTest(false) {
- return
- }
- defer endPCToSPTest()
-
- data, err := getData(pcsptestBinary)
- if err != nil {
- t.Fatal(err)
- }
- entry, err := data.LookupFunction("main.test")
- if err != nil {
- t.Fatal("lookup startPC:", err)
- }
- startPC, ok := entry.Val(dwarf.AttrLowpc).(uint64)
- if !ok {
- t.Fatal(`DWARF data for function "main.test" has no low PC`)
- }
- endPC, ok := entry.Val(dwarf.AttrHighpc).(uint64)
- if !ok {
- t.Fatal(`DWARF data for function "main.test" has no high PC`)
- }
-
- const addrSize = 8 // TODO: Assumes amd64.
- const argSize = 8 // Defined by int64 arguments in test binary.
-
- // On 64-bit machines, the first offset must be one address size,
- // for the return PC.
- offset, err := data.PCToSPOffset(startPC)
- if err != nil {
- t.Fatal("startPC:", err)
- }
- if offset != addrSize {
- t.Fatalf("expected %d at start of function; got %d", addrSize, offset)
- }
- // On 64-bit machines, expect some 8s and some 32s. (See the
- // comments in testdata/pcsptest.go.
- // TODO: The test could be stronger, but not much unless we
- // disassemble the binary.
- count := make(map[int64]int)
- for pc := startPC; pc < endPC; pc++ {
- offset, err := data.PCToSPOffset(pc)
- if err != nil {
- t.Fatal("scanning function:", err)
- }
- count[offset]++
- }
- if len(count) != 2 {
- t.Errorf("expected 2 offset values, got %d; counts are: %v", len(count), count)
- }
- if count[addrSize] == 0 {
- t.Errorf("expected some values at offset %d; got %v", addrSize, count)
- }
- if count[addrSize+3*argSize] == 0 {
- t.Errorf("expected some values at offset %d; got %v", addrSize+3*argSize, count)
- }
- }
-
- func getData(file string) (*dwarf.Data, error) {
- switch runtime.GOOS {
- case "linux":
- f, err := elf.Open(file)
- if err != nil {
- return nil, err
- }
- dwarf, err := f.DWARF()
- if err != nil {
- return nil, err
- }
- f.Close()
- return dwarf, nil
- }
- panic("unimplemented DWARF for GOOS=" + runtime.GOOS)
- }
|