• Ian Lance Taylor's avatar
    cmd/cgo: discard trailing zero-sized fields in a non-empty C struct · 7904946e
    Ian Lance Taylor authored
    In order to fix issue #9401 the compiler was changed to add a padding
    byte to any non-empty Go struct that ends in a zero-sized field.  That
    causes the Go version of such a C struct to have a different size than
    the C struct, which can considerable confusion.  Change cgo so that it
    discards any such zero-sized fields, so that the Go and C structs are
    the same size.
    
    This is a change from previous releases, in that it used to be
    possible to refer to a zero-sized trailing field (by taking its
    address), and with this change it no longer is.  That is unfortunate,
    but something has to change.  It seems better to visibly break
    programs that do this rather than to silently break programs that rely
    on the struct sizes being the same.
    
    Update #9401.
    Fixes #11925.
    
    Change-Id: I3fba3f02f11265b3c41d68616f79dedb05b81225
    Reviewed-on: https://go-review.googlesource.com/12864Reviewed-by: 's avatarRuss Cox <rsc@golang.org>
    7904946e
gcc.go 48.1 KB