}

          val bufferPos = upstreamPos - buffer.size

          // Bytes of the read precede the buffer. Read from the file.
          if (sourcePos < bufferPos) {
            return@synchronized SOURCE_FILE
          }

          // The buffer has the data we need. Read from there and return immediately.
          val bytesToRead = minOf(byteCount, upstreamPos - sourcePos)

	if f.baseErr != nil {
		return 0, f.baseErr
	}
	return addr - f.base, nil
}

func (f *file) BuildID() string {
	return f.buildID
}

func (f *file) SourceLine(addr uint64) ([]plugin.Frame, error) {
	f.baseOnce.Do(func() { f.baseErr = f.computeBase(addr) })
	if f.baseErr != nil {
		return nil, f.baseErr
	}
	return nil, nil
}

func (f *file) Close() error {

			// details for all the errors.
			for _, e := range list {
				fmt.Fprintln(os.Stderr, e)
			}
			os.Exit(2)
		}
		fatalf("parsing %s: %s", name, err)
	}
	return ast1
}

func sourceLine(n ast.Node) int {
	return fset.Position(n.Pos()).Line
}

// ParseGo populates f with information learned from the Go source code
// which was read from the named file. It gathers the C preamble

	}
	return nil
}

func symbolizeOneMapping(m *profile.Mapping, locs []*profile.Location, obj plugin.ObjFile, addFunction func(*profile.Function) *profile.Function) {
	for _, l := range locs {
		stack, err := obj.SourceLine(l.Address)
		if err != nil || len(stack) == 0 {
			// No answers from addr2line.
			continue
		}

		l.Line = make([]profile.Line, len(stack))
		l.IsFolded = false
		for i, frame := range stack {

			if i+1 < len(insts) && insts[i+1].Addr > inst.Addr {
				// Extend to next instruction.
				length = int(insts[i+1].Addr - inst.Addr)
			}

			// Get inlined-call-stack for address.
			frames, err := r.obj.SourceLine(addr)
			if err != nil {
				// Construct a frame from disassembler output.
				frames = []plugin.Frame{{Func: inst.Function, File: inst.File, Line: inst.Line}}
			}