On 07/30/18 18:01, Joseph Myers wrote: > On Mon, 30 Jul 2018, Jakub Jelinek wrote: > >> On Mon, Jul 30, 2018 at 03:52:39PM +0000, Joseph Myers wrote: >>> On Mon, 30 Jul 2018, Bernd Edlinger wrote: >>> >>>> In the moment I would already be happy if all STRING_CSTs would >>>> be zero terminated. >>> >>> 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. Thanks Bernd.
