needCSize := f.CompressedSize == ^uint32(0)
	needHeaderOffset := f.headerOffset == int64(^uint32(0))

	// Best effort to find what we need.
	// Other zip authors might not even follow the basic format,
	// and we'll just ignore the Extra content in that case.
	var modified time.Time
parseExtras:
	for extra := readBuf(f.Extra); len(extra) >= 4; { // need at least tag and size

			a.Offset = int64(r2)
			// Nothing may follow
			return
		}
		if p.arch.Family == sys.PPC64 {
			// Special form for PPC64: (R1+R2); alias for (R1)(R2).
			if prefix != 0 || scale != 0 {
				p.errorf("illegal address mode for register+register")
				return
			}
			a.Type = obj.TYPE_MEM
			a.Scale = 0
			a.Index = r2
			// Nothing may follow.
			return
		}
	}
	if r2 != 0 {

		for _, k := range nameKinds {
			if strings.HasPrefix(t, k+"_") {
				return true
			}
		}
	}
	return false
}

// rewriteCalls rewrites all calls that pass pointers to check that
// they follow the rules for passing pointers between Go and C.
// This reports whether the package needs to import unsafe as _cgo_unsafe.
func (p *Package) rewriteCalls(f *File) bool {
	needsUnsafe := false