cmd/link: fix gdb backtrace on architectures using a link register
Also adds TestGdbBacktrace to the runtime package.
Dwarf modifications written by Bryan Chan (@bryanpkc) who is also
at IBM and covered by the same CLA.
Fixes #14628
Change-Id: I106a1f704c3745a31f29cdadb0032e3905829850
Reviewed-on: https://go-review.googlesource.com/20193
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/runtime/runtime-gdb_test.go b/src/runtime/runtime-gdb_test.go
index 7cfcefc..4f82646 100644
--- a/src/runtime/runtime-gdb_test.go
+++ b/src/runtime/runtime-gdb_test.go
@@ -3,6 +3,7 @@
import (
"bytes"
"fmt"
+ "internal/testenv"
"io/ioutil"
"os"
"os/exec"
@@ -13,19 +14,22 @@
"testing"
)
-func checkGdbPython(t *testing.T) {
- cmd := exec.Command("gdb", "-nx", "-q", "--batch", "-iex", "python import sys; print('go gdb python support')")
- out, err := cmd.CombinedOutput()
-
- if err != nil {
- t.Skipf("skipping due to issue running gdb: %v", err)
+func checkGdbEnvironment(t *testing.T) {
+ testenv.MustHaveGoBuild(t)
+ if runtime.GOOS == "darwin" {
+ t.Skip("gdb does not work on darwin")
}
- if string(out) != "go gdb python support\n" {
- t.Skipf("skipping due to lack of python gdb support: %s", out)
+ if final := os.Getenv("GOROOT_FINAL"); final != "" && runtime.GOROOT() != final {
+ t.Skip("gdb test can fail with GOROOT_FINAL pending")
}
+}
+func checkGdbVersion(t *testing.T) {
// Issue 11214 reports various failures with older versions of gdb.
- out, err = exec.Command("gdb", "--version").CombinedOutput()
+ out, err := exec.Command("gdb", "--version").CombinedOutput()
+ if err != nil {
+ t.Skipf("skipping: error executing gdb: %v", err)
+ }
re := regexp.MustCompile(`([0-9]+)\.([0-9]+)`)
matches := re.FindSubmatch(out)
if len(matches) < 3 {
@@ -42,6 +46,18 @@
t.Logf("gdb version %d.%d", major, minor)
}
+func checkGdbPython(t *testing.T) {
+ cmd := exec.Command("gdb", "-nx", "-q", "--batch", "-iex", "python import sys; print('go gdb python support')")
+ out, err := cmd.CombinedOutput()
+
+ if err != nil {
+ t.Skipf("skipping due to issue running gdb: %v", err)
+ }
+ if string(out) != "go gdb python support\n" {
+ t.Skipf("skipping due to lack of python gdb support: %s", out)
+ }
+}
+
const helloSource = `
package main
import "fmt"
@@ -57,13 +73,8 @@
`
func TestGdbPython(t *testing.T) {
- if runtime.GOOS == "darwin" {
- t.Skip("gdb does not work on darwin")
- }
- if final := os.Getenv("GOROOT_FINAL"); final != "" && runtime.GOROOT() != final {
- t.Skip("gdb test can fail with GOROOT_FINAL pending")
- }
-
+ checkGdbEnvironment(t)
+ checkGdbVersion(t)
checkGdbPython(t)
dir, err := ioutil.TempDir("", "go-build")
@@ -162,3 +173,82 @@
t.Logf("gdb cannot backtrace for GOARCH=%s, skipped goroutine backtrace test", runtime.GOARCH)
}
}
+
+const backtraceSource = `
+package main
+
+//go:noinline
+func aaa() bool { return bbb() }
+
+//go:noinline
+func bbb() bool { return ccc() }
+
+//go:noinline
+func ccc() bool { return ddd() }
+
+//go:noinline
+func ddd() bool { return f() }
+
+//go:noinline
+func eee() bool { return true }
+
+var f = eee
+
+func main() {
+ _ = aaa()
+}
+`
+
+// TestGdbBacktrace tests that gdb can unwind the stack correctly
+// using only the DWARF debug info.
+func TestGdbBacktrace(t *testing.T) {
+ checkGdbEnvironment(t)
+ checkGdbVersion(t)
+
+ dir, err := ioutil.TempDir("", "go-build")
+ if err != nil {
+ t.Fatalf("failed to create temp directory: %v", err)
+ }
+ defer os.RemoveAll(dir)
+
+ // Build the source code.
+ src := filepath.Join(dir, "main.go")
+ err = ioutil.WriteFile(src, []byte(backtraceSource), 0644)
+ if err != nil {
+ t.Fatalf("failed to create file: %v", err)
+ }
+ cmd := exec.Command("go", "build", "-o", "a.exe")
+ cmd.Dir = dir
+ out, err := testEnv(cmd).CombinedOutput()
+ if err != nil {
+ t.Fatalf("building source %v\n%s", err, out)
+ }
+
+ // Execute gdb commands.
+ args := []string{"-nx", "-batch",
+ "-ex", "break main.eee",
+ "-ex", "run",
+ "-ex", "backtrace",
+ "-ex", "continue",
+ filepath.Join(dir, "a.exe"),
+ }
+ got, _ := exec.Command("gdb", args...).CombinedOutput()
+
+ // Check that the backtrace matches the source code.
+ bt := []string{
+ "eee",
+ "ddd",
+ "ccc",
+ "bbb",
+ "aaa",
+ "main",
+ }
+ for i, name := range bt {
+ s := fmt.Sprintf("#%v.*main\\.%v", i, name)
+ re := regexp.MustCompile(s)
+ if found := re.Find(got) != nil; !found {
+ t.Errorf("could not find '%v' in backtrace", s)
+ t.Fatalf("gdb output:\n%v", string(got))
+ }
+ }
+}
