On Thu, Oct 29, 2020 at 04:50:54PM +0100, Jan Hubicka wrote:
> * tree.c (build_string): Update.
> * tree-core.h (tree_fixed_cst): Avoid typeless storage.
Is it valid then to
#define TREE_STRING_POINTER(NODE) \
((const char *)(STRING_CST_CHECK (NODE)->string.str))
and strcpy etc. it around though?
Maybe yes, because stores through char can alias anything.
> diff --git a/gcc/tree-core.h b/gcc/tree-core.h
> index c9280a8d3b1..63dbb5b8eab 100644
> --- a/gcc/tree-core.h
> +++ b/gcc/tree-core.h
> @@ -1401,7 +1401,8 @@ struct GTY(()) tree_fixed_cst {
> struct GTY(()) tree_string {
> struct tree_typed typed;
> int length;
> - char str[1];
> + /* Avoid char array that would make whole type to be typeless storage. */
> + struct {char c;} str[1];
> };
>
> struct GTY(()) tree_complex {
> diff --git a/gcc/tree.c b/gcc/tree.c
> index 81f867ddded..84115630184 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -2273,7 +2273,7 @@ build_string (unsigned len, const char *str /*= NULL */)
> memcpy (s->string.str, str, len);
> else
> memset (s->string.str, 0, len);
> - s->string.str[len] = '\0';
> + s->string.str[len].c = '\0';
>
> return s;
> }
Jakub
