On Mon, Jul 30, 2018 at 04:28:50PM +0000, Bernd Edlinger wrote:
> >>> generic.texi says they need not be. Making the STRING_CST contain only
> >>> the bytes of the initializer and not the trailing NUL in the C case where
> >>> the trailing NUL does not fit in the object initialized would of course
> >>> mean you get non-NUL-terminated STRING_CSTs for valid C code as well.
> >>
> >> One thing is whether TREE_STRING_LENGTH includes the trailing NUL byte,
> >> that doesn't need to be the case e.g. for the shortened initializers.
> >> The other thing is whether we as a convenience for the compiler's internals
> >> want to waste some memory for the NUL termination; I think we could avoid
> >> some bugs that way.
> >
> > TREE_STRING_LENGTH includes the NUL if it is logically part of the object,
> > but should not if the NUL is purely an implementation convenience.
> >
>
> To complicate things a bit more STRING_CST that are created by the Ada FE
> for the purpose of ASM constraints, do not contain a NUL character.
> That is in TREE_STRING_LENGTH, there is of course always another NUL char
> after the payload. Likewise for C __attribute__ values.
If there is a NUL at TREE_STRING_POINTER (x) + TREE_STRING_LENGTH (x), that
is ok.
Jakub
