golang/go · error

no DWARF data in Plan 9 file

Error message

no DWARF data in Plan 9 file

What it means

Returned unconditionally by plan9File.dwarf() in cmd/internal/objfile. Plan 9 a.out executables do not embed DWARF debug sections, so the objfile abstraction reports that DWARF is unavailable for this file type. It is the by-design 'not supported' answer for the Plan 9 backend.

Source

Thrown at src/cmd/internal/objfile/plan9obj.go:149

func (f *plan9File) goarch() string {
	switch f.plan9.Magic {
	case plan9obj.Magic386:
		return "386"
	case plan9obj.MagicAMD64:
		return "amd64"
	case plan9obj.MagicARM:
		return "arm"
	}
	return ""
}

func (f *plan9File) loadAddress() (uint64, error) {
	return 0, fmt.Errorf("unknown load address")
}

func (f *plan9File) dwarf() (*dwarf.Data, error) {
	return nil, errors.New("no DWARF data in Plan 9 file")
}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Accept that Plan 9 binaries have no DWARF; fall back to the gosym table or Plan 9 symbol table for symbolization.
2. If DWARF is required, build for a target whose format carries it (ELF/Mach-O/PE) instead of plan9.
3. Detect the file type before calling DWARF() and skip the call for plan9 files.

Example fix

// before
entry, _ := objfile.Open(plan9Bin)
data, err := entry.DWARF() // "no DWARF data in Plan 9 file"

// after: branch on arch/filetype and use gosym instead
data, err := entry.DWARF()
if err != nil {
    // fall back to symbol table
    tbl, _ := entry.PCLineTable()
}

// Detect plan9 binaries before requesting DWARF.
func isPlan9(path string) bool {
    f, err := os.Open(path)
    if err != nil { return false }
    defer f.Close()
    magic := make([]byte, 4)
    io.ReadFull(f, magic)
    // plan9 magics: 0x0000eb00, etc. — use debug/plan9obj for robustness
    _, err = plan9obj.NewFile(f)
    return err == nil
}

func isNoDWARFPlan9(err error) bool {
    return err != nil && strings.Contains(err.Error(), "no DWARF data in Plan 9")
}

data, err := entry.DWARF()
if err != nil && strings.Contains(err.Error(), "no DWARF data in Plan 9") {
    // degrade to Plan 9 symbol table
    return nil
}

When it happens

Trigger: Calling (*objfile.Entry).DWARF() on an Entry wrapping a Plan 9 a.out (detected by plan9obj magic). pprof or symbol tooling reading a binary built for a Plan 9 target.

Common situations: Cross-building for Plan 9 (GOOS=plan9) and then running a pprof/DWARF-consuming tool on the resulting binary. Using objfile on a Plan 9 binary expecting the same debug data as ELF.

Related errors

• no DWARF data in go object file
• subprogram DIE high not convertible to uint64
• subprogram DIE high_pc not convertible to uint64
• subprogram DIE high_pc unknown value class %s
• multiple toplevel scopes

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/f2705030a0669b44. Report an issue: GitHub.