Tamar Christina <tamar.christ...@arm.com> writes:
> Hi All,
>
> Currently we segfault when len == 0 for an attribute list.
>
> essentially [cons: =0, 1, 2, 3; attrs: ] segfaults but should be equivalent to
> [cons: =0, 1, 2, 3] and [cons: =0, 1, 2, 3; attrs:]. This fixes it by just
> returning early and leaving it to the validators whether this should error out
> or not.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
>
> Ok for master?
>
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> * gensupport.cc (conlist): Support length 0 attribute.
>
> --- inline copy of patch --
> diff --git a/gcc/gensupport.cc b/gcc/gensupport.cc
> index
> 959d1d9c83cf397fcb344e8d3db0f339a967587f..5c5f1cf4781551d3db95103c19cd1b70d98f4f73
> 100644
> --- a/gcc/gensupport.cc
> +++ b/gcc/gensupport.cc
> @@ -619,6 +619,9 @@ public:
> [ns..ns + len) should equal XSTR (rtx, 0). */
> conlist (const char *ns, unsigned int len, bool numeric)
> {
> + if (len == 0)
> + return;
> +
> /* Trim leading whitespaces. */
> while (ISBLANK (*ns))
> {
I think instead we should add some "len" guards to the while loops:
/* Trim leading whitespaces. */
while (len > 0 && ISBLANK (*ns))
{
ns++;
len--;
}
...
/* Parse off any modifiers. */
while (len > 0 && !ISALNUM (*ns))
{
con += *(ns++);
len--;
}
Otherwise we could crash for a string that only contains whitespace,
or that only contains non-alphnumeric characters.
OK like that if it works.
Thanks,
Richard
