On Wed, 13 Dec 2017, Jakub Jelinek wrote:
> Hi!
>
> PR83391/PR83396 failed because debug bind stmts were put before labels.
> Alex said that is undesirable, and that right now we want to allow
> just debug begin stmt markers before or intermixed with labels.
>
> This patch ensures that through verification, which is what defines
> what is and isn't valid GIMPLE. If we ever reconsider it, either allow
> further stmts or disallow even debug begin stmt markers, we can easily also
> tweak the verifier. The patch has been successfully bootstrapped/regtested as
> part of the:
>
> https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00811.html
>
> https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00808.html
>
> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42861
>
> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42866
>
> https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00794.html
>
>
> patchset, without the msg00811.html patch it of course doesn't survive
> bootstrap, as we insert debug bind stmts before labels in those cases.
>
> Ok for trunk once the msg00811.html patch or something similar is committed?
Ok.
Richard.
> 2017-12-13 Jakub Jelinek <ja...@redhat.com>
>
> * tree-cfg.c (verify_gimple_in_cfg): Verify no non-label stmts
> with the exception of debug begin stmt markers appear before
> labels.
>
> --- gcc/tree-cfg.c.jj 2017-12-12 21:24:23.000000000 +0100
> +++ gcc/tree-cfg.c 2017-12-13 07:44:15.622790922 +0100
> @@ -5380,6 +5380,7 @@ verify_gimple_in_cfg (struct function *f
> err |= err2;
> }
>
> + bool label_allowed = true;
> for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> {
> gimple *stmt = gsi_stmt (gsi);
> @@ -5396,6 +5397,19 @@ verify_gimple_in_cfg (struct function *f
> err2 = true;
> }
>
> + /* Labels may be preceded only by debug markers, not debug bind
> + or source bind or any other statements. */
> + if (gimple_code (stmt) == GIMPLE_LABEL)
> + {
> + if (!label_allowed)
> + {
> + error ("gimple label in the middle of a basic block");
> + err2 = true;
> + }
> + }
> + else if (!gimple_debug_begin_stmt_p (stmt))
> + label_allowed = false;
> +
> err2 |= verify_gimple_stmt (stmt);
> err2 |= verify_location (&blocks, gimple_location (stmt));
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
