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[PATCH] Verify allowed stmts before labels
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>, Jeff Law <law at redhat dot com>, Alexandre Oliva <aoliva at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 13 Dec 2017 15:12:49 +0100
- Subject: [PATCH] Verify allowed stmts before labels
- Authentication-results: sourceware.org; auth=none
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
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?
2017-12-13 Jakub Jelinek <jakub@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