Re: Invalid tree node causes segfault in diagnostic

[Richard Biener <richard dot guenther at gmail dot com>]

On Fri, Oct 11, 2013 at 12:57 PM, Paulo Matos <pmatos@broadcom.com> wrote:
> Hello,
>
> I have a testcase that, during parsing, generates an invalid tree. This invalid tree triggers tree_check_failed, which was expecting a string_cst.
> tree_check_failed calls internal_error with tree_code_name[TREE_CODE (node)] without checking that TREE_CODE (node) is valid.
>
> I attach a patch as a suggestion of a fix. I would like some comments.
>
> This patch eliminates the segfault and generates the error:
> ../../../../../source/adsl-mech/components/common/PsdInfo.c:717:1: internal compiler error: tree check: expected string_cst, have (invalid code name) in get_named_section, at varasm.c:415
>
> This is obviously another thing I still have to understand why it's happening.
> The testcase is still too big (1Mb) and I haven't reproduced it with any upstream port so I am not reporting a bug yet.

Hmm.  We have several places accessing tree_code_name without checking.
May I suggest to abstract accesses to it with a function call which can
do the proper checking and return "<invalid tree code>" instead?

Thanks,
Richard.

> For the patch attached:
>
> 2013-10-11  Paulo Matos  <pmatos@broadcom.com>
>
>         * tree.c (tree_check_failed): Check that TREE_CODE is valid before
>         passing it to tree_code_name.
>
>
> Paulo Matos
>
>